[Excaliber]

The difference in price is often due to the type of material used. Walmart sells a basic 'dust cover' really cheap. But it won't stop rain, or sun damage, etc. The highest quality cover you can get is the one for outdoor use, intense sun. Like you would use to cover a boat. Problem is that material is heavy AND expensive!

As for using one to transport across country, I'd do a search here on CC for problems guys have seen using a car cover on an open trailor. NOT a good idea. The wind buffeting will for sure leave 'marks' here and there all over the paint. You can't tie it down or tape it down enough to stop the 'fluttering' that WILL occur!