If those prices sound expensive, there is always a possibility of doing them yourself. I have built maybe ten sets, it's no rocket science, just plain work. I have usually started with a header kit, they are about 200$ mild steel, Hooker & Hedman. First job is to determine hte length and diameter you want to choose the correct kit. Usually you need extra turns for the job, I usually take four extra J's to begin with. Next step for me is to make a "gasket" out of sheetmetal, with non holes except for the bolts. Then I tack weld about 1" tubs to the flanges and install them. Next I cut desired length pieces from proper size flexible paper hose, like used in many production cars air filter preheating system, adn attach tehm to teh stubs in teh flanges with hose clamps. Next, I find a location for the collector, and attach it there, tack welding it to its correct location. Then I start figuring out the proper routes to teh collector with those four flexible paper hoses. Once I get the best routing and roder figured out, it's time to start duplicating it with the steel pipes. Starting with the one that looks "hardest", from the flange tackwelding enough pieces to reach the collector + some extra removing the collector at this point. Then the next hardest pipe etc until all four are each tackwelded together. Usually takes 2-3 pieces per primary, I cut them with a regular hack saw. Then I remove them from the flange, and weld the joints completely, then tackweld again to the flanges and cut the collector end to the proper length. Next, I remove the assy, form the flange side pipes to the port shape, and fully weld them in a "jig", just a U- profile with bolt holes for the flange. Then I weld the primaries together in the collector end and fill the gap in the center. Next it goes back to the car again, and I slip the collector on and tack weld it. Out the assembly comes again, and I fully weld the collector; voila, a ready header! And the other side next. You have to keep in mind all the time, that you must be able to remove and install the header, the less room, the more difficult it is, and if you must make it disassembly able, it's even more work. But all it requires is some very basic metal skills, time and nerves. Fenderwells usually take one long day to build. There is some pics of my "one day headers" in the gallery; room to spare, no ground or wheel clearance problems.
http://www.bigblockdart.com/photopost/data/500/hiideri5.jpg
http://www.bigblockdart.com/photopost/data/500/hiideri4.jpg
http://www.bigblockdart.com/photopost/data/500/hiideri1.jpg
http://www.bigblockdart.com/photopost/data/500/hiideri3.jpg