If a player types "buymenu" or "buy" a buy menu pops up and allows the player to choose among pistols, shotguns, smgs, machine guns, rifles, and/or equipment. On the right of every weapon in the buy menu there is a shortcut that you can type into the chat box. For example, simply by typing "buy m4" it subtracts $3,100 from your reserves, drops your primary weapon, and gives you a m4.

/////////////////////Configuration\\\\\\\\\\\\\\\\\\\\\\\\\

/// Time until zombie spawns
/// repeat start buy_buytimer Time 1
repeat start buy_buytimer 40 1

///////////////////End Configuration\\\\\\\\\\\\\\\\\\\\\\\

Change the 40 to the time that your server takes to spawn a zombie, in seconds.