My bedroom is small, I have back issues, and I'm not willing to buy pre-made steps at the prices I can find. So I made a set of steps that is lightweight, takes up as little space as possible, and is fairly inexpensive. Bonus: it was quite easy and perhaps it will help someone else with a not-so-mobile--
In Take 1 (http://www.instructables.com/id/Dog-stairs-for-bed-take-1), I made something very pretty but that my dog ultimately could not use.
In Take 2, we'll see something that she finds much more usable, if requiring slightly more in the way of expenditure and hardware.