Each year students in my investing class had to investigate individual retirement accounts (IRAs) and mutual funds to select the best fund for their IRA. With tight budgets, student loan payments looming after graduation, and credit card balances, saving for retirement was NOT their top priority. But after seeing examples of compound interest and how their money could grow over the 4+ decades before they anticipated retirement, they became experts at finding the lowest cost (in expense ratios and minimum initial investments) target retirement date funds (and index mutual funds). Schwab had the lowest initial minimum of $100 but only for stock index funds. Vanguard was the place for target date funds with the lowest minimum investment of $1,000 (0.14-0.16% expense ratio) but requires $1,000 to open the account.
But now Schwab has cornered the market on lowest initial investment, lowest expense ratio, target index funds. You can't beat their ultra-low 0.13% expense ratio for diversified mutual funds that automatically become more conservative over the decades as retirement approaches. see for yourself: