The Gymnastics Life
About 7 years ago I resolved to save my former boss some cash and make our own spotting blocks. After all, it could not be that hard since its just styrofoam, foam, and vinyl. Here's how it went.
Locate styrofoam companies. I was able to find two in our area. The one I use is StyroTech. They can make any size block you could ever want. Example below.
Next Step is to cover the Styrofoam with a protective layer of foam. I've used scrap pieces of 1.5-2" trocellen foam as well well as an older 1/2-5/8" vault runway. Recently I had success asking an equipment company that we placed an order with to send as much extra 5/8" scrap foam as they had (they sent it at no charge). I was able to get enough to cover 4 of our larger spotting blocks.
You can glue the foam pieces on but I've opted to heavily duct tape them. It's not pretty but who cares once the covers on? It's faster, more secure, and will more than likely never need to be replaced.
The last step is to have the covers made. I order my vinyl from MyTarp (they sell it by the yard). You'll have to do some math to figure out how much you need. You'll then need to find someone to sew the covers. The first people we used charged $35 per cover and they did an OK job. They made the covers like a pillow case with velcro caps at the end, it wasn't aesthetically pleasing but I couldn't complain for $35.
Recently, I've used our local tailor and they do it for $59-$69 depending on the size. These covers have a zipper and look tenfold better. Example below.
I'm not exactly sure how much we have saved but I'm sure it's a lot. Just doing some quick math:
A 2' x 2' x 4' styrofoam costs $35-50 per piece. The scrap foam was free. Duct tape was about $10. Each cover was $59. So about $110-120ish per 2' x 2' x 4' block. Obviously the smaller the Styrofoam the costs goes down. There's also is volume discounts and the person who sews your covers may be cheaper.
Good luck. If you have any questions feel free to reach out.