[Kar]

pawn Код:

new DealerVeh[4];

    DealerVeh[0] = CreateVehicle(542,358.1000100,-78.9000000,1.2000000,180.0000000,105,88,15); //Clover
    DealerVeh[1] = CreateVehicle(540,362.1000100,-78.9000000,1.4000000,180.0000000,156,161,15); //Vincent
    DealerVeh[2] = CreateVehicle(533,366.8999900,-79.1000000,1.2000000,180.0000000,54,65,15); //Feltzer
    DealerVeh[3] = CreateVehicle(549,371.3999900,-79.0000000,1.2000000,178.0000000,77,50,15); //Tampa

public OnPlayerStateChange(playerid, newstate, oldstate)
{
    new vID = GetPlayerVehicleID(playerid);

    if(newstate == PLAYER_STATE_DRIVER || newstate ==  PLAYER_STATE_PASSENGER) // you can change this
    {
        if(vID == DealerVeh[0])
        {
            ShowPlayerDialog(playerid, DEALER_CLOVER, DIALOG_STYLE_MSGBOX, "Purchase Vehicle?", "Buy for $825", "Buy", "Cancel");
        }
        else if(vID == DealerVeh[1])
        {
            ShowPlayerDialog(playerid, DEALER_VINCENT, DIALOG_STYLE_MSGBOX, "Purchase Vehicle?", "Buy for $1,250", "Buy", "Cancel");
        }
        else if(vID == DealerVeh[2])
        {
            ShowPlayerDialog(playerid, DEALER_FELTZER, DIALOG_STYLE_MSGBOX, "Purchase Vehicle?", "Buy for $2,250", "Buy", "Cancel");
        }
        else if(vID == DealerVeh[3])
        {
            ShowPlayerDialog(playerid, DEALER_TAMPA, DIALOG_STYLE_MSGBOX, "Purchase Vehicle?", "Buy for 1,000$", "Buy", "Cancel");
        }
    }
    return true;
}

Or that.

1. You don't know if the guy is gonna create those after he already created 255 vehicles.

2. Bad condition check