Tax deeds and redemption period

[Jeremy Bridges]

Good evening everyone. I have a few questions regarding tax deed sales and the redemption period for the owner.  This is for TN and it's a deed state with 1 year redemption. I've heard some use property owners that are still in their 1 year redemption period as a source of leads.  I've read a wise decision after purchasing from a tax sale would be then to follow up with the owner and try to buy the property to get the redemption rights as well, especially before putting any more money into the property.  So say the person who purchased the tax deed did not follow up with the original owner and was just going to wait out the year to take full ownership of the property.  What if I was able to speak to the owner and offer to buy the property to get the redemption rights and then start the redemption process.  Here's where I get a little confused. 

1. This might be a silly question but I just want to be clear.  If the original back taxes were $4,500, but the person paid $45,000 at the tax sale.  Would you have to pay the $45,000 plus the interest or the back taxes and only the interest on the $45,000 and the state would give back the difference?

2. I know there would be penalty fees and court cost associated with redeeming the property as well.  What would normally be a ball park figure of those fees?

3. Is this a feasible strategy?

Any one that can share actual experiences would be very helpful.  Sorry if this was a little drawn out, but it's late and couldn't fall asleep with this running through my head.  Thanks for any advice or tips.