It's a lot more complex than that. Usually these deals have tax liabilities and liens that aren't chargeable unless the city agrees to it. Anyone can tell you, there is nothing more expensive than a free house/boat/car.
St. Louis is the market I’m most familiar with, but I’m sure it’s the same everywhere: it’s not just taxes and liens; it’s that most of the properties are worth less than the cost of making them habitable. Every municipality has occupancy requirements and building codes. Any house you can buy for $100 in Detroit is going to cost roughly the same (or more) as new construction to meet these codes. In St. Louis, for example, you’re required to present construction plans and hard timelines as a condition for purchasing abandoned property. They aren’t going to accept your optimistic DIY dreams. They have to be real plans at market rates. And if you don’t meet the agreed-to dates, you lose the property.
A lot of these properties literally have a negative value; it would cost more to renovate them and complete environmental mitigations on them than is profitable. When you see a property for $100, you almost certainly wouldn’t want it unless you were paid to take it.
Use common sense; there’s a reason these properties were completely abandoned by their previous owners.
These are usually handled through city property auctions. Bidding usually starts at a few dollars. But you have to read the fine print. They will usually have city, county, state, federal, and private liens on them.
For example a federal treasury auction will discharge IRS tax liens but not state, county, and city charges. I've seen $1mm beach-side homes auctioned for <$100k. But then have $500k+ in state liens on them.
A savvy buyer will get the titles and try to get the liens discharged by negotiating with the other agencies or pay them off. This is factored into the offer they will make on the property. If you think you've stumbled into a method to get rich quick you're sadly mistaken.
