Something

enum VehicleEnum{
vOwner[MAX_PLAYER_NAME],
ownerid
}

new VehicleOwners[MAX_VEHICLES][VehicleEnum];

public OnPlayerConnect(playerid)
{
	if(VehicleOwners[MAX_VEHICLES][vOwner]==PlayerName(playerid)){
	ownerid=-1;
	}
}


dcmd_buycar(playerid, params[])
{
    #pragma unused params
    new vid=GetPlayerVehicleID(playerid);
    if(IsPlayerInAnyVehicle(playerid) && checkpoint[playerid]!=CAR){
    checkpoint[playerid]=CAR;
    SetPlayerCheckpoint(playerid,2127.4976,-1134.5254,25.5596,20.0);
    SendClientMessage(playerid,COLOR_SYSTEM,"Please go to the checkpoint marked on you map with your car");
	}else
	if{checkpoint[playerid]!=CAR){
	SendClientMessage(playerid,COLOR_SYSTEM,"Please get in a car to do this");
	}
	if(IsPlayerInAnyVehicle(playerid) && IsPlayerInCheckpoint(playerid)){
	if(GetPlayerMoney >=CarCost[playerid]){
	GivePlayerMoney(playerid, -CarCost[playerid]);
	VehicleOwners[vid][vOwner] = PlayerName(playerid);
	ownerid=-1;
	Car[playerid]=vid;
	SendClientMessage(playerid,COLOR_SYSTEM,"You have bought this car!");
	}else{
	SendClientMessage(playerid,COLOR_SYSTEM,"Not enough money to buy this");
	}
    
    
	return 1;
}