Ebay and national websites most likely will not be a good choice because the tires most likely are not worth what it would cost to ship them. Most likely you are selling them because they are old but still have good tread. You do not have any information on your profile about what type of RV they came off of. If they are a tire that could be used by a trucking company you may be able to sell them to a operator of a small dump truck company to use on their tag axle. Most of the large trucking companies don't have the time or want the liability of dealing with used tires. Put them on CL for a reasonable price and they will sell quickly but don't expect to get much.