Try a site like Cafe Press to make and sell them. If you just want to sell them, try eBay.
GetGlue
A really good site to get custom stickers from is Sticker You, its a really easy site to use and their stickers are built to last and durable, you can create your sticker on site.
Yamaha decals and stickers can be purchased from a large variety of online retailers. Motorcycle sellers often sell replacement stickers and decals, to allow a motorcycle rider to customize their vehicle. Also, a site called FastDecals sells a variety of replacement or additional decals for many purposes.
A obvious site would be EBAY. You can also try an online site to create your own store.
One can order free stickers from various retailers and wholesalers online. The type of stickers and retailers that offer them will vary by location and site.
Name stickers, as well as other custom products can be purchased from Vistaprint. Zazzle is another online site where a person can purchase custom stickers.
Stickers come in different forms, depending on the purpose. There are stickers for fun, especially those intended for children and you can get it from grocery stores. And there are also stickers that have a serious purpose like your car stickers, or company stickers which are used for promotion or branding. Companies and businesses used personalized stickers to create an identity or label of their own in the industry. You can check some great designs and samples of personalized stickers to this site: http://www.uprinting.com/sticker-printing.html
Someone looking to find a list of local stock of Harley stickers could find them online on a site like amazon. Also checking Harley sites would help in finding Harley stickers.
The unique aspects of the iweb are the internet tool to create online sites. The people can access it & use it to create business site or their non-business site online.
There are many online retailers that sell a Barbour Liddesdale Jacket. This includes the Barbour site, as well as sites such as Amazon and the auction site eBay.
Any online costume site should sell women's costumes. I suggest trying a site with a lot of selection such as http://www.costumecauldron.com/ or http://www.halloweencostumes.com/
First determine the value. Once you have that you can sell it to a collector, trade it, or sell it on an online auction site such as eBay.