Answering the age old question i.e. What is something worth? with the answer being What someone will pay for it. Sorry about the pic quality but can't save eBay pics anymore, so dig camera copies.
1/ 'You are bidding on a Lotus Cortina or Ford Escort Twin Cam Brake servo, it looks in great condition but not sure if it works cause i dont have the car to try it on.'
Auction end price - GBP 293.10 [ 21 bids ] Approximately AU $450.03