Firearms are purchasable for much cheaper than what they are listed as.

Basically, it's an attempt to help balance out the weapons - items that
are in higher demand get a higher pricing, while lower demand items are
priced lower.  This tries to cut down on some items having the
best-bang-for-the-buck by tweaking the prices slightly.

Of course, I tried the beta myself - couldn't use the GUI to start any
maps since it only has "<Random Map>" in the selection dropdown,
followed by a crash shortly after.  (Could be a downloading issue...)