I built my own scissor steps out of steel angle and flat strap, with 3/4" plywood treads. Really it's not that difficult, just a lot of careful measuring, cutting, measuring, and drilling. No welding, as the treads hold the two frames together.
Loads of improvement over "monkey climbing" into the camper off the trailer hitch the first year, and the step stool I used the second year.
Only problem I've had is one tread delaminating because of the poor-quality box store plywood. I am replacing the treads with solid oak this winter.