They might well be a legit retail operation, but I wouldn't bother with that reseller "opportunity."
1) Either doesn't understand the concept of MAP or hopes resellers don't
2) "Allows" (!) one to sell on eBay, but if you do the warranty is void on anything you sell. This does not even parse -- thousands of items are sold with warranties every single day on eBay. There are a few possible explanations for this restriction, none of them paint a very flattering picture of RC Hobby Explosion
3) $80-$120 non-refundable "application fee" to become a reseller. Pfpht. Look up the individual manufacturers and ask about their wholesale arrangements. If they use distributors they'll connnect you to the nearest one; if they wholesale directly they'll let you know what you need to do to become a dealer.