I like the flimsy thin nursery buckets. Reusable and flexible so you can cram them together if needed. If it's a small grow, look over the bank at the cemetery and you'll find them there for free. As a side note, I went to a buddy's to check out his outdoor grow this year. Ten foot tall plants loaded with gnarly buds. He ended up with 14# from 20 plants. The buckets? Used 5 Gallon Hydraulic Fluid buckets. Not my recommendation, but impressive none the less! And definitely cheap. Scrub 'em up, fill 'em with your medium of choice and grow, baby, grow!