The Sleeper family may be living in a cave, but they're still acutely aware of the economic crunch.

The suburban St. Louis family has a big payment due in May on its cave home and is worried about losing the unusual property.

So as a backup plan, Curt and Deborah Sleeper are putting the house up on eBay's online auction block. Bidding for the home wedged inside an old mining cave starts at $300,000.

The home has electric, water and sewer, a decked-out kitchen, whirlpool tub and a goldfish pond. Inside, the walls and ceiling are comprised of the natural cave stone.

It also comes with a star-studded history. In the 1960s, the cave was a roller rink that hosted concerts, including shows by Ted Nugent and Bob Seger.

The family paid about half of the $160,000 purchase price for the cave up front. The rest of the property costs are due in May.