Prices are at all price points, most lower than retail, but some not. Why go? To meet and hang with hundreds of other like minded hobbyists, attend the lectures and demos and learn something, meet and develop personal relationships with vendors, support the MR community ( this board continues to exist because of the $$ MR makes at the events) and shop the largest coral market in the tri-state area. If you are looking for bargains, the MR selling bins have cheaper items for purchase and vendors do often run specials throughout the day.
The biggest reason to come is to have fun, which I think the vast majority of past attendees will attest is exactly what happened.