I've paid $120 or $130 for a clam (noae & crocea respectively), but have never spent more than $60 on a frag. I may pay more for a really nice noae, but that's my limit (and my vice) on clams. I've been fortunate enough to trade some awesome corals with fellow reefers, which is my preferred method. I kinda wish that we would trade more in this hobby, especially amongst hobbyist. The only time I sell frags is either to fund equipment purchases or I have too much of something, but if that's the case then I usually try to lower the price or wind up giving a lot away for free or in trade. Whenever I thought about how much money I could make from selling frags, the reefing gods always seem to humble me, so for me, it's about paying it forward and banking corals with friends and like-minded reefers. To me, the only coral that's worth it's price is the purple monster. It's one the few corals in this hobby with true lineage (there are others) and worth it (to me). I think we all have that "one" coral we would pay more money for and the purple monster is mine.
Happy reefing!