Just go to an office supply store and buy computer printable blank business cards and design and print your own. Do the same with computer iron on t-shirt paper. This is the method I use and it's cheap, easy and fast.
Cagepress and zazzle have print on demand service for dedigns you upload, may not be the cheapest.
I have been seeing a $4.75 1/2 price offer from Vistaprints advertised after searching for: t-shirt drop shipper.