Try for a tire about 1-1/2 times wider on the outside, than the rim is on the inside. There should be a decent selection, and you don't need to spend anywhere near $50.00 for quality bike tires. They may not be top recognized brands, and may be slightly heavier, but that doesn't mean they can't serve you well for general purposes.

FWIW, I use tires that retail for under $15.00 for my commuter, and they hold up as well as anything else might, lasting until a large glass shard makes a cut too big to repair.