You don't necessarily need to use branded tubes to safely send you parcels. Amazon.com as well as staples.com offer a wide range of cheap alternatives.
Mailing tubes, the sort of thing one would mail a rolled up poster in for example, are available from stationery stores. In the UK this includes Ryman, Staples and UK Office Direct to name but a few.
There are a multitude of places to order mailing tubes. You should be able to find one in any fedex or other shipping store, but you can also buy them online at http://www.uline.com/cls_15/Tubes , http://www.yazoomills.com/mailing-tubes.aspx?utm_source=google&utm_medium=cpc&utm_term=mailing+tubes&utm_campaign=Yazoo+Mills+Tubes-+Strategic+Keywords&gclid=CI780vOAoKACFSJ25QodW1K7ag , or http://www.staples.com/Mailing-Tubes-Mailers-and-Mailing-Tubes/cat_CL141868 .
You can pick up mailing tubes for posters from your local post office.
Mailing tubes are tubes that one can put mail in. Generally, it is best for shipping things that are long, or tube shaped. They can be found at any post office.
Maximum length for a mailing tube is 34 inches for the standard rate for Priority Mail. Larger mailing tubes may require additional postage. Call 1.800.ASK.USPS to inquire about tubes that exceed 34 inches.
Here's one place where you can buy them: http://www.tubesrus.com/packaging_materials/paper-tubes/heavy-duty-mailing-tubes/default.html. They take custom orders.
Yes, mailing tubes do come in a variety of sizes and strengths. To learn more about the various sizes, visit www.usps.com and www.ups.com.
Plastic mailing tubes are sold at Bestvaluesupply, Quill, Office Depot, OfficeMax, Staples, Reliable Paper, The Office Dealer, ShippingSupply, and ReStockIt.
One can purchase cardboard mailing tubes at many local office supply stores, large retailers such as Wal-Mart, or at a local postal or shipping store.
You can try online retail sites such as Amazon and eBay. These websites also sell shipping tubes: http://www.officemax.com/office-supplies/shipping-mailing-supplies/mailers-tubes, http://www.officedepot.com/a/browse/mailing-tubes/N=5+530025/ and http://mailingtubesonline.com/.
Bulk mailing tubes can easily be purchased online at United States Postal Service or at UPS or FEDEX or even in person at the United States Postal Service.
Mailing tubes are available at the post office and in office supply stores or departments. Many shops that sell posters or other larger paper goods also have them, and you can also try Fed Ex and UPS stores. You can find mailing tubes at most office supply stores, such as Office Depot or Staples. You can also find some online at www.uline.com, which sells a variety of mailing products.