Banks, thrifts and credit unions offer money market accounts. These are government-insured accounts that allow you access to the money you have deposited. Withdrawals are limited to six monthly, three of which may be by check. These accounts earn interest with the rate varying widely. Banks that are trying to attract deposits often offer MMAs with higher yields. Yield also vary on the amount deposited: The more you deposit, the more you earn.

Bankrate.com regularly surveys financial insitutions and publishes their money market account rates. Click here to search for a money market account for you.

Money market funds are a type of mutual fund. Each share is worth $1. That value never changes. But the return on the investment does fluctuate. Earnings are paid as dividends to shareholders. Although the deposits made in these funds by shareholders are not insured by the government, money market funds are a relatively secure investment. Under government regulations, these funds must go into high quality short-term investments. Investors also can write checks against the balance invested in these funds.

Both accounts and funds are used to "park" cash and still maintain liquidity. Other types of investments offer higher long-term return.