Here is the latest property I bought at a tax deed sale about 5 months ago. Its all of the property immediately to the right of the island, including the submerged land.
(I subsequently purchased the island in an unrelated transaction). The light shaded area is the buildable area of the tax deed property, which comprises about 1.8 acres. The property is zoned multi-family and is assessed for around $250,000. I bought it for $30,000. I wouldn't take $500,000 for it.
So, you can get a good deal at tax deed sales, at times. But, it has gotten harder. In my county, tax deed sale info is now available online. Obviously, this means more people know about them, thus, competition is stiffer.
Firms now send out mailers offering "help" to people with delinquent taxes. So, some of the properties get redeemed before going to sale.
Often times the properties that I see come up are distressed properties that need work, and/or are in less desirable areas. Every now and then, a quality property comes along, but those are the ones that bring out the bidders.
Every state is different, but in Fl., the successful bidder takes the property free and clear of all liens, mortgages and encumbrances, except Federal, state and municipal liens.