If you contact Gemini and ask for there upto date brochure you will get all the rig tying info you will ever need. It shows you pully rigs, flappers, booms, distance, pennel etc etc. In it it gives you the measurements of the different droppers, main line, hook sizes etc to be used. Don't be afraid to experiment yourself. It's not rocket science and you can adapt the measurements to suit your own style of fishing. I can tell you now, The money you are thinking of spending would fill your rig wallets over and over again if you are making the rigs yourself and you catch you really get a buzz from catching on a self tied rig.
All you need to start would be a spool of 60lb line for your main body, a packet of crimps to suit the line your using, a few small 3mm beads and a packet of small swivels. The dropper line can be really anything but usually about 20lb to 25lb line to counter the tide and stop it tangling. Use whatever size hooks you would normally use ie. size 1 and away you go. That's the basis of a flapper rig. 5-10 minutes ties it up and away you go. If you loose it your really not out of pocket.
On a damp evening tying traces is better for you than sitting watching TV or looking at the better half, although don't let on for god sake.
Steve