I got mine from a place in Abilene, TX called D & D Gates and Panels. They don't have a website. The panels that I got are 10' long by 6' tall and they are heavy duty pipe instead of the bendable aluminum tubing. On average (freight was slightly different on every load) mine were about $55 per panel.
I have done well with auctions and Denver CL. I have bought Horseman's Edge 6x12 panels for less than $60 average. Get a Fence Post and look for upcoming auctions. There are a couple of panel makers that advertise in there as well. My RP is a WW that I got at Ackerman's (LaSalle) and it was crazy expensive years ago but worth every penny.