Personally, unless your dog is destructive and has issues with a crate, I don't see a reason to spend a lot of money on one of those aluminum boxes. I don't see why any regular crate wouldn't work. If you go to eBay you can see a variety of sizes and they are all much cheaper than in stores.
I've bought 4 different crates off of eBay, a 48" one that is only at home has no rust on it (not sure why rust would be a worry inside). The others are constantly used in vehicles and my dogs have gotten into them muddy/wet and still no rust on those either. At the end of the day, I'd rather spend $35-$45 on a crate, and then just get a new one if that one breaks (not sure why it would though) in a decade.