upgrading 10g tank question

[pandafishowner]

Right now I have a 10 gallon tank with 5 guppies in it. I have one of those clams that attach to an airline pipe and pump that makes bubbles, a 2 barrel decoration, and the large gem like stones. I want to upgrade to a 20 or 30 gallon tank, but I don't want to pay a fortune for a tank stand. All the ones I've seen are double the price of the tanks. I already have the heater, filter, and more stuff. I'm wondering a few things: I've seen some people use tv stands for fish stands, was wondering if it's safe enough. What other kind of fish can I put into the tank with the guppies. Does it *have* to be a planted tank? I don't want to deal with babies and so far my guppies haven't had any. I'd prefer not to use real plants. Will they still breed if the plants are plastic and small? How many fish should I have in a 20 gallon if that's what I go with? My 5 guppies are all around 1.5inches long. I want colorful fish, mostly guppies. I have 2 rams horn snails and a few baby ones, though they tend to disappear after I've seen them, think the fish eat them. Finally: what should I use as a cleaning crew when I get a new tank? A cory cat or an oto? Thanks