I have. 2 shakers screwed into the underside of my ikea office chair. Both powered by a small 50w smsl amp.
The shakers were SinusLive 4 or 8ohm ones iirc. I'll find the box later & let you know. Think there were around £30 each ( on offer at the time )
Currently use SimVibe for the vibration effects, but SimHub works pretty well too. It just takes a bit more tweaking.
Btw if you do go the SimVibe route, you'll ideally need a 2nd sound card.
Overall I'd say it's well worth it. Especailly if you play any of the rally titles.
Well apart from WRC 8 that is. It doesn't put out the telemetry data needed iirc.
There's also 'pre-built' seat padding options out there but I can't remember their name/s. Both GamerMuscle & SimRacingGarage reviewed them a while ago.
Think overall they're more expensive - £150+ - but might be worth considering for a less hassle option.
It's also worth checking out the sim racing hardware forum over at RaceDepartment, as it has a lot of info on different setups/equipment people have tried, etc...