Valve recently announced that weapon pricing within Counter-Strike: Source is going to be fluctuating according to market demand. This new dynamic weapon pricing system
is going into effect on October 11, 2006.
Previously, the weapon pricing is fixed, which led to some weapons being heavily favored by players. This really restricted the range of weapons utilized in combat.
The new dynamic pricing encourages players to consider alternative weapons that may be cheaper when cash is low. It increases the gameplay competitiveness.