[link]All of my full-color button/shirt designs have now been organized into a single comprehensive page and have all been added as buttons and magnets to Customdesignprinted.com, where they cost only $1.50 - $3! I'd recommend the $2 mid-size.
Don't feel bad if you already bought them super-expensive from zazzle; these cheaper ones do print a little fuzzier, and tone down my shading and highlights. They still look neat though, and oddly the black backgrounds are more accurately BLACK on the cheapo buttons. Zazzle's are a little bit grayer in person.
Some links might be messed up, just let me know and I'll fix them as soon as I can.