EDIT: SOLDI'm selling my Buttkicker Sim Kit; I had it attached to the base of my flight sim chair.
Goes for $220 new (actually $176 after the 20% discount they currently have):
https://thebuttkicker.com/bk-sk/Although I forgot to show them in the attached picture, I do have the 6 rubber isolators shown on the website.
Price is $110 which includes shipping within the U.S.
I don't know why the picture is attached upside down, but I can't figure out how to fix it.