I have 3-steps for the living room to get up/down from the furniture (mine is kinda butted up in the corner, so they can run from the loveseat to the couch without problem). I have 5-steps in the bedroom to get up/down on the bed. The bedroom stairs would take up a lot of room if they were perpendicular to the bed, but I run them parallel, so they only take up the width of the stairs (in this case, 12").

I know you can get the 3-steps at Target, but I think they're a little more expensive ($19.95? $29.95? - they're the ones you see on the TV info-mercials).

At any rate, these dogs are so tiny, and the grooves in the knee that allow the bones to move are correspondingly tiny (and shallow). They are prone to something called luxating patella (LP for short), which means that their knees pop out. It's crippling and hurts like the Devil, not to mention expensive to fix. So anything you can do to help prevent the stress that causes it is a good thing.

If you can't afford stairs, stack books or something. Tie boxes together. Do something, because I don't think it's a good thing for them to jump. Some are daredevils and you can't stop them, but most can be taught to avoid this unnecessary danger.