Cushions

I would like (and really need) to acquire a good quality cushion. I Googled hoping to gain some info. I did, gain some info. Seems the most likely cushion that I need is "equagel general" for $295.00.
My question is... are there similar cushions out there that cost less than $295,00?
There are DEARER cushions of course. Much much dearer. But are these rather expensive items really worth that expense or is the same quality cushion selling for much, much less.
Other people's experience would help me decide. I'm on my bum 97% of the time, and suffer from degenerative disc disease... aka arthritis in the lower spins. Sitting down alleviates the pain. Thanks for any reply.