I attended my first tax sale this year. I had a total bank roll of $80k and planned to spend most of it. I was spending a bunch of time digging through the TS list, so I decided to hire a VA to cut the list down to size for me. I spent about $24 for six hours of their time to reduce the list from ~200 properties to 20 which met my initial winnow.
Of that list, I decided to make offers on six properties.
The day of the auction, three of those six properties had been paid, so I was now only bidding on three properties.
One of the properties was worth about $175k on the market, the other two, about $20k in their current conditions or $75k when repaired.
I got into a bidding war with another couple for the $175k house but decided to not pursue above $35k because of some liens on the property and because the other couple kept checking zillow and using a calculator every time I raised them. I figured they were too new at this to know when to stop.
I won one of the other homes for $4,500. It was a 2/1 about 200 yards from the local elementary school with one third of an acre of land. Improved, the 2/1 would rent for $650/month + utils. About two weeks after the purchase, I received a phone call from the previous owners interested in buying the house back. I waffled on this point, but learned that in Pennsylvania, if the previous owners initiate proceedings w/in 60 days of a tax sale, they are able to retain the house and I would only receive my money back.
After much consideration, I sold the house back to them for $6,000, a return of 33% in three weeks.
Back to the drawing board for new properties, but a family is happy and I was happy with the return from this 'investment'.
33% in three weeks, I think I would take that too. We buy a lot of tax sales, they are a great way to buy properties below market value. In Delaware we have a 90 redemption period. In the first 30 days you get no interest, after that you get 10-15%.