Don't forget to also check AIH and RiteBrew. AIH and AustinHB sell loose and 4 packs of new kegs (also used ones) for a fairly decent price. There are others doing similar things.
Most use the Taprite regulators with the large red knob(s).
To see who gives you the best bang for the buck, stick some of the prices in a spreadsheet, see how they add up. Include shipping charges into the totals. If you have to order from more than one place or use multiple shipments, extra shipping charges can wipe out differences quickly.
The tank is a fairly large $$ purchase and unless you can get it filled locally, you'll end swapping your brand new tank for a used one that won't look half as good. So check around. Check Craigslist for a used tank, perhaps with regulator.
Read around here on kegging and what people use.
You'll need a temp controller for your serving fridge. Get an Inkbird 106 or 108, not an analog one.