A repo will be sold at an auto auction. You can find these open to the public in major cities, although there often will be an admission charge to the auction.

In smaller towns, the auctions are not public, or repos are sold privately to dealers who then ask the going price without much discount.

It may be possible to contact local lenders who typically finance car loans. They would be agreeable to reasonable offers for the repos they have. This is as long as it is beneficial to them to sell at your offering price, so as to save them the trouble of dealing with the car.

However, large lenders generally have set patterns in place for dealing with their repos, and would not be available for any bargaining directly with an interested buyer.

With a few phone calls, probably you can find a reliable contact in your area who would be willing to sell at a 50% discount, as long as the lender gets back its loan, plus the expense of the repossession and extra red tape the lender had to go through.

Sheriff auctions are a great place to find repossessed cars for cheap. You can sometimes buy trucks and cars from GSA auctions too.