I saw 3 bird cage that would be perfect for a hedgehog because you could build a second level onto it! And then put in a tube for the Hedgie to crawl down so the site is called www.kijiji.com it is like Ebay except everything is ALOT cheeper! Try it out!
Unless you get into large parrot cages, most bird cages are not suitable for hedgehogs. Bird cages are tall and narrow and hedgehogs need horizontal space, not vertical. The doors on most bird cages are not large enough to get wheels and igloos through. Bird cages also have grates on the floor which would need to be fully covered or removed. If removed the slide out tray would need to be firmly attached or I could see a hedgie escaping through it, same with the openings where the food goes.
Many of the large parrot cages would work with modification. With the extensive modifications that most bird cages would require to make them hedgehog safe, I can't see they would be any better a deal than to just buy a proper cage in the first place.