farm auctions is a great place to pick up used equipment, you can go talk to a local dairy supply store, they may have used equipment to buy from them also. Thats what we did, we bought a pipeline systwm from a retired dairy farmer down the road, its old but it still works, we bought a used Mueller Bulk tank, that our future fieldman found for us, had the surge dealer come out and install everything so it worked, that was pretty expensive, and this took about 2-3 years, we raised up calves until they were cows, and started slow.
If you want a overnight barn, its gonna cost more money, I know a guy just built a barn from scratch fancy automatic take offs, the whole 9 yards, up to date and fancy, milking 16 at a time, 32 in at one time, he has about $300,000 into it, milking 105 first calf heifers which he had already, don't know if he owns them free or clear, but at these milk prices I would advise the least debt as possible.
Good luck