On the AMP boards... I haven't looked in awhile at prices all over the net, but the place I got mine has them for 1299.99 with the plug and play module. There is also free shipping and no sales tax if you live outside of Arizona. So 1299 out the door. The company is Quality Bumper. You will get the warranty as well. The used to run 10, 15 or 20% coupons, (none currently unfortunately). I had a great experience overall with them and can recommend them. Again, not sure if this is the cheapest price out there, but an option.
Not sure if the $100 rebate will work through them though. Might be worth looking into.
http://www.qualitybumper.com/runningboards_sidebars_steps/powerstep/Default.asp