I haven't done it myself but a reg. plastic flower pot and a power drill might solve the problem. lay out a grid pattern and drill the intersecting lines. 1/4 - 3/8" bit should be good to make the holes.
get the size of pots u want to grow get a reazor blade and heat it up with a blow tourch then go to work on cutting lines in your potworked for me,,,but time consuming
anything that has a nice lip around the top edge. Cut the hole large enough for the cup (or whatever you use) to fit in the hole, but small enough for the lip on the top of the edge to support the container you choose. Anything made of plastic that you can cut holes in the bottom will work. Make plenty of holes at the bottom for the roots to grow out of and your good to go.
Yogurt cups. Drill lots of holes around it. Or like they have said, Dixie cups with a soldering iron or a drill work well also.