On a budget I go to stores that actually stock that model and extra that model sizes and I bring the socks my husband uses for walking... A quick way to check fit is to pull the insole out and stand on it to see if his forefoot hangs over. If it does the shoe is not truly that model enough even if the box says that model.
Ask the staff about slip resistant outsoles and look at the pattern yourself. You want real rubber with grooves that will shed water rather than a mostly smooth bottom. Some stores allow returns after a short outdoor try on clean pavement which is helpful when you need to see how the grip feels in the real world.
