If I sell my second house for more than I payed for 20 years ago, do I have to pay taxes on the difference?

Answer 1

You are entitled to $250,000. in profit as an individual. $500,000
as a married couple.
If you bought your home for $30,000 20 years ago and sell it for
350,000. today and then turn around and buy another home for 250,000 ( if your downsizing) you gain a profit of 100,000. That's way below the amount necessary to pay a tax. You will also be able to factor in things like points on a new mortgage. There is also a stipulation on the amount of time before you invest into your new home.

Check this link out for a further explanation--
http://www.bankrate.com/brm/itax/news/taxguide/home-gain1.asp?caret=18