Manny66 

I used Rollers for many years back in the 80's and 90's, they are great for cycling training but have very little resistance so your workout is more Technique oriented, (imo) . I never put them in a doorway like alot of people suggested, I had mine near a wall and would occasionally lean against it using my shoulder to get going and for slowing down.
I eventually wore out the rubber o ring band that ran the drums so it was a chore locating a replacement. I was in Hawaii at the time and there was no internet invented yet so it took months to replace it.

Ive seen some selling for under $ 30 now a days, I paid almost $300 for mine way back when.