You should expect 250 without shipping for a base rack kit, 25 for locking cores if needed, and close to 70 for a used bike tray setup. I'd estimate around 350.
I'm using a Thule base rack setup. 38" fairing, though I prefer the 44 if I can get a trade sometime, and a Yakima Anklebiter deuce bike tray. Yes you can mix and match, with proper adaptors. Those are pretty cheap. I'd say best bet is buy a full kit on craigslist, and just swap the fit kits(60$). I've seen proper full kits go on craigslist for 150 dollars.
Specs you need:
Thule:
50 Inch load bars (Model LB50)
38 or 44 inch fairing, both work fine.
400xt feet. theres, also a newer more expensive aero feet, which work with the aluminum aero bars.
Fit kit: 2155 for 400xt, not sure for the aero
Yakima:
48 inch load bars
38 or 44 inch fairing, both work fine.
yakima q towers
fit kit: Q78 i believe. i gotta check.
i did plenty of research before I found mine. I originally wanted a Yakima kit, but found a Thule one first, and I love it.