1.5mm out of true isn't too bad. If there are no huge WOOPs in the rim (my technical term for a bad spot that sort of woops in and out) a good mechanic should be able to get it pretty true. As a mechanic myself I will try to true a wheel for about 5 minutes if it is really bad and then make a decision. If I feel that the spoke tension will be too variable and I won't be able to get the wheel as true as I want it I will call the customer and tell them it's gonna cost them $20 and the wheel will be usable but probably not stay true for that long. If the bearings are toast I will also note that the labour alone on a rear hub overhaul is $20. And that to get this wheel in decent riding shape it will cost them in the area of $50 or more and that they should think about buying a new wheel... if the hub is of good quality we will recommend a new rim.