Invest in real estate or pay down mortgage?

[Suzanne Roberson]

We have inherited $90,000 and are trying to decide what to do with this money.  We owe $140,000 on our home at 4% interest (home is worth approx. $250,000) .  My husband, who is 65, is a contractor and has a profitable business and I have a degree in Art, Interior Design.  We have thought about flipping houses but we also have thought about paying down our mortgage. Or both. With the current market, we just didn't know if this is a good time to purchase a home to start flipping. And then again, at our age, we need some security by paying down the mortgage.  All suggestions would be appreciated!