www.redbubble.com/ is where I order my stickers! You can open a shop on there for free, and order from yourself for an Artist Price rate (which is cheaper than public price). The stickers are re- stickable, vinyl and last quite a while. Some fading may occur, but for mine it's mostly only been if the sticker was placed on top of anything with a not flat texture underneath. If you buy at least 6 stickers, they mark down the price for you. As for listing your art on items for sale, it's definitely worth doing! Even if sales are slow, the idea of not having to pay to list them (nor having to make the items yourself, only thing you do is upload the image + set it on their templates online) is a total plus.

I make buttons!
I use the button press machine I have at home, which makes 1.25" round pinback buttons (size is like the small sort at Hot Topic).
Which, if you have a rough time finding a site online to use, if ever you'd want some buttons made of your art, I could do made to order buttons using my machine & ship them to you for a bundled cost. Just pop me a note if ever wanting to try that out. (: 

example of one of my own button:

(price for a bundle to make your art into buttons I would be able to do for cheaper, since the art on it would be yours.)