I almost started breeding guppies years ago and I began with about thirty tanks, but there was no market and way too many fish. I could've filled every tank in a matter of months. I would highly recommend looking into one of the easier egglayers instead. They are a bit more difficult to breed but you're more likely to have a place to send all those fish. Especially if you don't breed one of the super high end guppies and cull carefully, you'll have a lot of plain or low quality fish that no one wants to buy. I don't want to put a damper on your plans, as I had lots of fun with guppies in smaller tanks that I wasn't trying to sell, but you really don't want to become overwhelmed and discouraged.
It's not a dumb question if you ask it.
Too many tanks? GASP! How could that be?