You can get free wholesale shipping boxes on BoxGiver
Yes, USPS offers boxes. You can buy them online or in your local post office.
You can purchase boxes in numerous places online. USPS offers free shipping boxes online. You can also purchase them from Staples or Office Depot online.
The USPS offers shipping boxes for it's customers. These are available for free on their website.
Generally the prices on the USPS website and what you pay in the store will be the same. You can actually get free boxes from local stores like Wal-Mart or Shaws. USPS will provide free boxes if you plan on using Express or Priority mail, too.
National chains such as Walmart or Target will have shipping boxes available for a reasonable price. You could also try shipping stores such as the UPS store or similar to get boxes. Also, the Post Office sells boxes. If you ship Priority Mail the boxes are free. The USPS is a good source if you need a handful of boxes. Check out these sites if you need to purchase in bulk/wholesale: http://www.papermart.com AND http://www.mystarsupplies.com AND http://www.packagingsupplies.com
USPS does offer bubble bags in all sizes online.
There is no standard for USPS shipping boxes, size and type all depend on what you are shipping. You can go to the USPS website and order many different sizes and types of boxes, envelopes, and labels for no charge. They will deliver them to you also at no charge.
The fastest shipping method is overnight shipping, offered by USPS, FedEx and UPS. It is also the most expensive. The most economical fast shipping option is USPS's priority mail flat rate boxes that deliver in two days.
A mailing box can be purchased at many office supply stores and shipping agencies, as well as online. Office supply stores such as Office Depot and Office Max carry generic shipping boxes, while a UPS store or USPS location will carry prepaid boxes and shipping labels.
The USPS have a few dozen rules and regulations regarding shipping boxes. To receive a complete list of all regulations, visit www.usps.com.
The US Postal Service offers free boxes. These are restricted to use through the USPS.
Uline has great prices on shipping supplies, but doesn't sell as many "cute little" types of things. Uline has bigger discounts and is geared more toward shipping, NashvilleWraps focuses more on retail packaging. They both have bubble mailers and kraft boxes. I mostly use USPS priority boxes and envelopes, and I get my tissue paper from Uline. :)