@Anarchy is right if you don't have too many funds to gamble with. It is a safe long-term bet. This is th eone I use:
Market Summary > Fidelity® 500 Index Fund
MUTF: FXAIX
121.94 USD +0.82 (0.68%)
Aug 28
Another with a strong balance sheet is MAIN (a principal investment firm that primarily provides equity capital to lower middle market companies and debt capital to middle market companies)
NYSE: MAIN
30.61 USD +0.14 (0.46%)
Aug 28
*Just remember to put more money into either periodically (weekly, monthly, quarterly) in order to grow your investment*
Example: I bought S&P 500 when I knew nothing (a friend recommended it). It more than doubled through the years but I NEVER bough more shares of the fund. When I finally sold my very small position ($1,000), it was $2,000+-->but could have been way more had I periodically placed some money into the fund.
Hope this helps