If this is a front leg, casts usually don't work. There is only a 5% chance they will work on that leg, especially if in the wrist area. As for the plate, that sounds way too cheap...is this a board certified surgeon who is doing this?? If not, I strongly suggest you find one for a second opinion. The problem that sometimes occurs with some vets doing cheap fixes is that they often don't do it correctly; and I have seen pups end up losing their legs. We have a foster who came to us after the owner had tried such things...the boarded surgeon we used tried bone grafts but they failed and the pup lost his leg.