Hello wondrous people

I am looking for a powerblocks rack stand. I found one on Amazon, but the price is astonishing (more than for powerblocks themselves). Can you recommend me some substitution for it? I tried to have them on a bench, but the bench is a little bit too soft and I was not able to change weight while I had powerblocks on it.

If I have them on the ground I cannot change weight fast enough and my knees are not happy to get up with weights. 

Thank you very much