Um, why is used stuff bad? All my tanks are used except for the 10g, and I've never bought a leaky used tank. All their filters, lights, and stuff are also used except for the heaters, and all work great. Plus they were all very cheap. $50 isn't going to go very far for a new set up... have you checked out the prices of stands alone new?
You don't really need to worry much about possible chemical use, just rinse it very well before you fill it. You can clean with diluted bleach too, and then rinse that really well and rinse again with some extra-dechlorinated water.