[bartje01]

pawn Код:

dcmd_buyskin(playerid,params[])
{
new skinid;
if(sscanf(params,"d",skinid))
{
SendClientMessage(playerid,0xFF0000FF,"Use /buyskin [skinid]");
return 1;
}
SetPlayerSkin(playerid,skinid);
GivePlayerMoney(playerid,-100);
return 1;
}

tested and works
If you want to make it free, delete the GivePlayerMoney(playerid,-100);