If you want to keep rats as pets you are better off building them a cage. 1" x 1/2" wire is awesome for building rat cages. The large mixing tubs from Home Depot make great bases for cages. Just make a wire "cube" with an open bottom, that fits inside the foot print of the mixing tub. Add some shelves and some door and you are good to go.
You can build the king of all rat cages for way under $50 oif you do it right!