Check out
signwarehouse.com. I buy most of my sign supplies from there.
As for certain types of transfer paper, I believe it's just personal preference. There are different brands, I use Conform. They can come in clear (better for stickers) and a masked color. They also come in different sizes, from 2-3" to 30" on up.
This site will give you information on the vinyl you buy (basic application instructions, longevity, etc).
I hope sending you this link is not against policy. But I think it'll help.