While cheaper doesn't necessarily mean better, you will find some of the cheapest S&P 500 funds that you can buy with $10,000 or less listed below.
2. Fidelity Spartan S&P 500 Index Investor Class
Symbol: FUSEX
Net Expense Ratio: .10%
Minimum Initial Investment: $10,000
3. Vanguard 500 Index Fund Investor Shares
Symbol: VGINX
Net Expense Ratio: .18%
Minimum Initial Investment: $3,000
4. SSgA S&P 500 Index Fund
Symbol: SVSPX
Net Expense Ratio: .18%
Minimum Initial Investment: $10,000
5. USAA S&P 500 Index Fund Member Shares
Symbol: USSPX
Net Expense Ratio: .23%
Minimum Initial Investment: $3,000
6. T. Rowe Price Equity Index 500 Fund
Symbol: PREIX
Net Expense Ratio: .37%
Minimum Initial Investment: $2,500 taxable account, $1,000 IRAs