The Buttkicker G2 works pretty well. I used to own one, until my cat dumped a glass of iced tea into the amp.
Since then I’ve used this bundle instead, Dayton Audio APA150 Amp With 2 Aura Pro Bass Shakers Bundle
It’s a two channel setup, and I have one transducer mounted under each butt cheek. I use simshaker, and I use my motherboard’s onboard audio as a dedicated sound card for simshaker.
IF anyone has an old home stereo or car amp lying around, they could just buy two Aura Pro transducers for $100 and us them with simshaker.