Another vote for the Zilla Critter Cage. Shop around though, as I've seen them for quite a variety of prices in the pet shops near me. Definitely make sure that both sides of the lid are positioned along the ridges and that lid is fitted under the clasps at the back. And, like Nanci suggested, it's good to give it an assurance tug to make sure it's locked in place. Sounds complicated, but it's not. It's one of the securist, most readily available cages on the market. I love the little cut-outs it has for cords too.
However, if you're looking for a cheaper, temporary solution, esp. if you are wanting to upgrade in the future, you could go for a Critter Keeper or Sterlite container. Either one could be secured with binder clips, elastic bands, velcro, bungee cords, and numerous other ideas I've seen on here.