Because I'm on a "make everything myself" kick, I did some of my own promo stickers.And because I'm feeling really nice, I'll tell you how I made them!
Stamp making supplies (see this tutorial)
Square paper punch
Xyron 150 (1.5" wide) sticker making refill (NOT the actual sticker maker)
To start, you'll want your own image for the stickers. I used some of my bug stamps I've carved myself previously. You can also draw your own images, but stamps will be much quicker once they're made. You can also make a stamp with your business name, or write it out yourself.
Use the square paper punch to make pieces to use for the stickers. The squares should be just under 1.5" wide. Also cut strips of paper for the top label of the sticker pages where you'll have your business name/website/other info.
Now go crazy with the designing! And once you've got your images ready, you can begin with the Xyron refill sticker making paper. You can use either the permanent or repositional.
First carefully pull out the bottom sticky sheet (don't touch the sticky part!). Start placing your stickers on the sheet facing right side up. Put them in groups of however many you wish, I did three, and make sure to leave spaces between them so you can affix your label.
After you put on a small group of images, cut them off the roll. Then take the top "rub and peel" part, and place it carefully over the top of the bottom sheet, making sure to cover the whole thing. Then rub with your fingernail over every gap, making sure not to miss any spots. The rub and peel paper will pull off the extra stickiness.
Then, pull off the rub and peel sheet, and you've got stickers! Just cut apart the sections you wish, and staple a piece of paper with your business info to the top.
You can of course do variation of shapes and sizes depending on the punches you have and the size xyron sticker making supplies you use. Hope this helps :)