As with all retro collectables, any object is only worth what someone is willing to pay for it. Your best bet is to list it in the relevant section on here (with an 'offers' sale pitch), or ebay them. Bear in mind that these are the type of ebay prices I see in the UK (If you're in the US, just substitute £ for $):
Jamma PCB's: £10-£50
New'ish' Jamma Loom: £20
Working used monitor: £60-100
Power supply: £10
Second-hand controls: £5-£30