Get some FiveTen Freeriders if you get any mtb shoes. They're about $80.
The main advantage to having mtb specific shoes is they grip the pedals better. You don't want your foot to slide off the pedal when you go over a bump. If you can't get mtb shoes then try to find a pair of shoes that has a flat but rubbery sole.
Personally I've found that even between mtb shoe brands the rubber matters and FiveTen has the best that I've tried.