The beauty of this system is that when the stock slumps, you are buying more. When the stock is pricier, you are buying less. Dollar-cost averaging is an especially good way to accumulate shares if you budget is limited, like most of us. Also, buying regularly through divident reinvestment plan is a form of dollar-cost averaging. For your 401k and Roth I.R.A., you should see what your investment options are.
Mutual funds are a good investment product.
Mutual funds mainly invest in over 100 companys, instead of just one. That way it makes your investment safer, and you do not but all your eggs in one basket. Most mutual funds that have no loads perform better than mutual funds that have loads. So, look for no-load mutual funds to invest in. A good no-load mutual fund company is T. Rowe Price.