A similar upgrade is available in the store for Champions Online, for the exact same price -- but it increases the number of costumes available on every character rather than just the character it's purchased on. The per-character upgrades, coupled with a reduced importance for costumes in Star Trek Online, all help make many players feel a bit shorted by the price tag. Others are arguing that the add-on is only $2.50, an argument that's gone on at length on the official forums. Controversy is nothing new to the game, but this much debate over a fairly minor item leads one to be a bit curious about what reception future items might find.
[Update: Cryptic has contacted us with news on upcoming changes to this system, "We're going to change the way the costume slot purchases work so they become account-wide rather than per-character. And, of course, our customer service department will be able to assist anyone who purchased the upgrade multiple times to cover multiple characters."]
[Thanks to Cap for the tip!]