Are prices on coins going down the tubes?

I've been collecting and selling for over 40 years but I'm new to internet selling/buying. It would appear that prices of coins are taking a hit (-25-30% on Modern issues) as of late and I was wondering if this is a seasonal drop? After reading the previous post where JimL4004 got the deals (or steals) on his Peace Dollars, it would seem that something is going on. Any thoughts on this from some of you more vetern internet sellers?