I help people to weed the errors out of their books. Fact checking, supplying references and the likes. So I get review copies, or as collectors prefer to call them 0-editions, ARC's [advance reading copies, if you will]. And when the final draft gets published - the 1st edition - I get a stack of signed, dedicated newly printed ones in return, as a form of payment. One for me, one for the archives, and the rest is being auctioned off for the benefit of Tibet. So, in the end, we all benefit in one way or another.