Step selection
Hi Mary-
I have the "Reebok" step. It is a great one. It is long, and also has the ability to be at 3 different heights, the third being fairly high. (Which is great, because you can put it on an incline for chest work when strength training) I think it is a little expensive, I bought mine about 5 years ago, and it was about 80 bucks. However it may have come down in price since then.
Watch for the deals, sometimes they will give you a video -free- with it.
Good Luck on your purchase!!!