Ideas for making my own T-Shirt..?

I was thinking of taking a couple white T-shirts and putting some letters on them. Any idea on how I could spray paint them on or some other method without paying $20+ a T-shirt

If you use spray paint make sure to put something maybe like an old towel or maybe even cardboard inbetween the paint will bleed through fyi

Stella McCartney – Her support and the ideas behind her POD Tshirt design