We have a plastic tote box (one of the 19 gallon ones) next to the bed. It's not pretty but it's functional.
We first put it there for our 18 yr old cat, she could no longer jump on the high bed. Once we let Charlotte sleep on the bed we put a blanket over it so she could get up too. She wouldn't use it before because it was too slippery without something on it. She's only 3 lbs and our bed is really high but it's perfect and cheap! LOL