In our area, we go to AgriSupply for items such as this. They have quality items and reasonable prices on farm and agricultural supplies. You might also try a local FCX store.
The best place to look would be your local farm and ranch store; if there is one near you. You can give them a call to find out if the have the item in stock, and if they do not they can order one for you.
Check at your local feed store. They always have an array of feeders out front on display. Find one that is best for you. If you only have one or two goats you could just buy rubber dishes for grain.