We did a large area, and it ended up fairly inexpensive, compared to other options.Cattle panels are great but EXPENSIVE if you have a large area. I started out with them but have since added on and use this original panel area as a holding pen when I need to do work in the pasture. USE ELECTRIC FENCE! This will greatly simplify your life and make having goats a lot less frustrating. I use two strands in addition to the cattle panels or other existing fence (one near the bottom and one at or above the top). Goats will get through fences. They pushed over the cattle panels at an angle and then jumped/launched themselves over and out. I also have a couple goats with horns. They were getting stuck in the panels and other fencing. This all ended when I put up a couple electric strands. I ran 5 wire electric (4 hots, 1 ground) where there is no pre-existing fence.
Also, don't cheap out on your fence energizer. Goats are stubborn and take a lot bigger shock than most other animals to deter.