5. You can build a gerbilarium
Alternatively, you can build a gerbilarium. While a cage usually only has wood shavings and a few pipes thrown in, a gerbilarium is an enclosure that you build from the ground up to mimic a gerbil’s natural habitat. You can find instructions on the Internet; it can be an interesting project. You can buy the largest tank that you can afford and put in a series of tunnels.