How Much Do Mailing Bags and Postage Bags Cost? A UK Price Guide

If you've ever grabbed a pack of mailing bags from the Post Office and winced at the price, you're probably already wondering whether there's a cheaper way to do this. There is, and the difference is more significant than most people expect.

This guide breaks down what postage bags, mailing bags and parcel bags actually cost across the most common places to buy them in the UK, what drives the price differences, and whether free shipping bags are ever actually worth having.

What do mailing bags cost in the UK?

The honest answer is that it depends almost entirely on where you buy them and in what quantity. The same bag can cost anywhere from a few pence to well over 30 pence per unit depending on the source. Here's how the main options compare.

How much are mailing bags at the Post Office?

Post Office mailing bags are among the more expensive options available. At the time of writing, small packs of parcel bags from the Post Office typically work out to between 25 and 40 pence per bag depending on the size. They're sold in small quantities, usually packs of five or ten, which means no bulk discount and a consistently high unit price.

The Post Office is useful if you need one or two bags immediately and have no other option. It is not a sensible place to buy packaging if you're sending more than a handful of parcels a month.

How much are parcel bags from supermarkets and stationery shops?

WHSmith, Ryman and larger supermarkets all stock some form of mailing bag. Pricing is broadly similar to the Post Office at the lower end, and sometimes higher. Pack sizes are again small, which means no meaningful discount for buying more. You're paying for the convenience of picking them up alongside other shopping, not for value.

How much do shipping bags cost on Amazon?

Amazon sits somewhere in the middle. You can find mailing bags in larger pack sizes, which brings the unit price down, and competitive sellers on the platform do price aggressively. A pack of 100 standard grey mailing bags on Amazon typically ranges from around 4 to 12 pence per bag depending on the size and seller.

The variables to watch out for are bag thickness and seal quality. Not all Amazon listings provide useful specifications, and quality across sellers is inconsistent. A bag at 3 pence per unit that splits in transit or has a seal that fails is more expensive in the long run than a slightly pricier bag that does the job reliably.

How much are mailing bags from a packaging supplier?

Buying directly from a specialist packaging supplier gives you the best combination of price, quality consistency and range. At Mr Bags, mailing bags are priced on a volume basis, meaning the unit price drops as the quantity goes up.

At lower quantities you're typically looking at a similar price to a well-priced Amazon listing. At higher volumes, the unit cost comes down considerably. For businesses sending a significant number of parcels each week, this makes a real difference to packaging costs over the course of a month or a year.

You can see current pricing across all sizes on our mailing bags page.

Where to buy cheap postage bags without compromising on quality

Volume is the main lever. The unit economics of polythene bags are straightforward: the more you buy, the lower the cost per bag, and that relationship is consistent regardless of where you're buying from. The difference is that a packaging supplier's bulk pricing is almost always better than a marketplace's, and the quality floor is higher because suppliers stake their business on consistent product rather than individual transactions.

A few practical tips for keeping costs down:

• Work out how many bags you actually go through in a typical month. If you're sending 30 parcels a month, buying in packs of 500 rather than 25 or 50 will cut your per-bag cost significantly and means you're not reordering constantly.
• Standardise the sizes you stock. Keeping two or three sizes that cover most of what you send means you can buy larger quantities of each, which gets you into better pricing brackets. Trying to have a perfect size for every scenario means lots of small orders at higher unit prices.
• Don't sacrifice thickness for price. A bag below 50 microns for standard clothing parcels is a false economy. Bags that split in transit cost you far more in reshipments, refunds and buyer complaints than the few pence you saved per bag.

Where to buy cheap shipping bags specifically

The same principles apply to shipping bags and parcel bags as to mailing bags. The terminology is interchangeable and the products are essentially identical. If you're searching for where to buy cheap shipping bags, a packaging supplier offering bulk pricing is your best starting point.

Avoid buying cheap shipping bags from sources that don't list bag thickness or material specifications. A price that looks good on a general marketplace can turn out to be a false saving once you're dealing with bags that fail under normal postal handling.

Can you get free mailing bags or free shipping bags?

This comes up a lot, so it's worth addressing directly. There are a few ways to access free or heavily subsidised bags, but they all come with caveats.

Carrier-provided bags

Some couriers and postal services provide free packaging for specific service tiers. Royal Mail's Special Delivery service, for example, has included free packaging for certain account types in the past. Evri and DPD occasionally run promotions for business account holders. In these cases the bags are provided at no direct cost, but you're usually restricted to using that carrier and the bags are branded, which may not be appropriate for all sellers.

Platform promotions

Vinted and eBay have at various points offered free or discounted packaging materials to new sellers or as part of promotional campaigns. These are worth taking advantage of when available, but they're not a reliable ongoing supply. Basing your packaging operation on a promotion that might end is not a sensible long-term approach.

Are free shipping bags actually worth it?

In most cases, no. Free bags from carriers or platforms tend to be branded, limited in size options, and available only in small quantities. They're a nice bonus but not a substitute for a proper supply of the sizes you actually need. A consistently stocked supply of the right bags, bought at a sensible price from a reliable supplier, is worth more than occasional free bags that may or may not be the right size or quality.

The real saving is not in finding free bags; it's in buying the right bags at the right volume from the right supplier so that the cost per bag is as low as possible for something you actually want to use.

How much are parcel post bags for businesses?

For businesses sending in volume, the pricing conversation shifts. At higher quantities, a packaging supplier will often offer trade pricing or account pricing that goes beyond the standard tiered discounts available to individual buyers.

If you're a business sending more than a few hundred parcels a month, it's worth getting in touch directly to discuss what that looks like. The unit cost at trade volumes is substantially lower than retail pricing, and having a reliable supply agreement in place means you're not managing stock shortages or inconsistent quality across different orders.

You can get in touch through our site or browse the full range to get a sense of current pricing at different quantities on our mailing bags page. If you also need boxes, tape or labels alongside your bags, our full packaging range covers all of these.

Summary: what you should expect to pay

To give a straightforward comparison across the main sources:

The figures above are approximate and will vary by bag size, material thickness and supplier. They're intended to give a realistic sense of the range rather than precise current pricing, which changes over time.

The takeaway is simple enough. If you're sending parcels regularly, the Post Office and supermarkets are the most expensive ways to buy bags by a significant margin. An online packaging supplier at bulk quantities is where the unit cost becomes genuinely low, and the quality is more consistent than buying through a general marketplace where you don't always know what you're getting.