I have a suggestion...
Have you looked into Kritter Keepers? Like from the reptile/rodent section? They're great on a budget, are very light and easy for water changes, come with a top to prevent jumping, and can be safely heated. They may not come with a light, but its easy enough to rig up something with a lamp(provided said lamp doesn't give off heat enough to affect the temp of the water)or other small LED light made for other tanks if you REALLY want a light.
The Medium KKs are about 2.5 gallons I believe....and the Larges are around 5 gallons.
Just something to think about ;) A neat, cheap tank alternative.