Cat food alternative? Please help

Hi all. I haven't been here in quite awhile. My computer got spyware, so it had to be fixed. Maybe you remember Mason, my longhaired black and white boy kitty. He's had issues with awful struvite crystals since basically day 1. He eats Hill's Prescription Diet c/d. The other 2 do as well. It's just too hard to separate them. I pay about $38 for a 20 lb. bag. Which, I really don't mind, considering it keeps Mason healthy and without the pain of those darn crystals. But is there a less expensive food out there? With the way gas prices are rising, not to mention the possible giant expense of heat this winter, it'd really help out to save even $5 on a bag. I know Nutro makes some really great food, and I am absolutely not willing to compromise on quality. I guess I really don't know where to start in my search and any help I will gladly accept.

Thank you,
Kristl, Mason, Thor, and Angel

Talk to your vet ... also visit the holisticat site... they have homemade reciepes... Max cat by nutro is certified but unless the vet okays it I wouldnt... So Ask your vet ... Do your research ... and homemade is a little less expensive... Oh and ask about wet food , it is better for them get specifics on magnesium and phos from the vet

i dont know any cheaper cat food of that sort but good luck in your search