What he said ... a proper running shop is what you need. Tell them your budget up front. You should find shoes that are right for you.My local Sweatshop has usually got a few pairs of something on offer.
Top of the range running shoes these days have price tags of up to £150, which is taking the piss imho.
Do the decent thing and buy the first pair in-shop after getting the advice and help, and then scour t'internet, ebay etc for replacements.