Sterlite tub from walmart/target works just fine when properly set up.
Edited for tips: Major tip is that if you use belly heat: ie UTH or Flexwatt be sure its on a thermostat. You don't want to deal with belly burns.
With a plastic tub I'm not sure if you can set up heat lamps or not, but ball pythons can successfully be kept in aquariums with attention to humidity. Its generally a bit more difficult to get that right than in a tub but it can be done with minimal effort.