Cheap board that supports crossfire

I am trying to build a new PC on a tight budget. I am going to get a 4850, and I thought down the line maybe it would be worth it to add a 2nd one, so I am looking for a crossfire supported motherboard. I have read that boards that have a 16x pci slot and a 8x slot are not ideal for dual gpus. All of the cheaper boards I have seen seem to have this setup. Are there any decent boards out there with dual 16x slots that are reasonably priced? Is it still worth getting a board with a 16x and 8x slot? Or since I am on a budget should I just forget about crossfire down the road all together?