It is not the perfect idea but may help you if cost is a big factor.
Go to Dick's or Sports Authority -- take a look at the shoe. Determine what pair you want to buy.
Go home and get on-line. You should be able to find the same pair, or a pair with a very close model number -- maybe a dead model number but essentially the same shoe. You should be able to pick up a decent pair of trainers for $40.
Like I said, it is not the perfect idea but maybe the most practical.