[!] buystage = CreateDynamicRectangle(Float:965.7295, Float:963.1254, Float:993.6744, Float:998.1960, -1, -1, -1, 0);

public OnPlayerEnterDynamicArea(playerid, areaid)
{
    if(areaid == buystage)
    {
        DisableRemoteVehicleCollisions(playerid, 1);
    }
}

public OnPlayerLeaveDynamicArea(playerid, areaid)
{
    if(areaid == buystage)
    {
        DisableRemoteVehicleCollisions(playerid, 0);
    }
}