The original Killing Floor has some paid weapon DLC available, but all maps were free. Do all players have access to all weapons in KF2?
As of the 6th Sept 2018, there is a second "paywalled" weapon in the beta (to be released to all with the next Halloween update):
Road Redeemer for the Berserker ( requires purchase of Road Redemption )
The weapon is basically a baseball bat with some metal additions at the extremity.