$4.99 vs. $5.00? And what do you call your premium memberships?
pospischil: I've always liked just having a single number e.g. $5 instead of $5.00 or $29 instead of $29.99.There has been loads of research done on this topic though.  Here is a quick link to what wikipedia has:
http://en.wikipedia.org/wiki/Psychological_pricing