It's really hard to make a living off liens unless you buy large quantities or you buy the higher priced liens in states that have higher interest rates.You can also try your hand in seeing if you can pick up the properties free and clear but the chances of that happening are slim to none since most home owners end up paying the back taxes before the redemption period expires.

Your chances of getting the seller to pay you are very slim.  

Slim to none on that anyway.Personally I have lost a lot of money on land deposits and unfortunately so will my investors.

But I think you know as well as I do the chances of that happening with everyone involved in real estate investing is slim, for a variety of reasons. 

The odds that this is a deal are pretty slim.

I sense that I have a slim chance, but if you don't make an offer then you will never know.

While the deals are slim, they come from time to time but qualifying for the purchase is extremely difficult without having tenants in place. 

If it can be done in 4-6 weeks as Andrew stated, that isn't too bad and can be planned, but if the process is takes 3-4 months, or longer, as Abhi suggested, that could be problematic especially if financing and/or working with slim margins.  

Have the margins slimmed there as well?

I have a model that looks at a portfolio 3% DP loan assumption and even after 1.4% rent to purchase price ratio and the 50% rule, my cash flow is REAL slim per month.