I'd recommend renting from your library, then if you really like a book you can buy it and annotate it. I do this myself and it has a lot of benefits - if I know I'm going to love and annotate a book I'm looking to buy, I'll spend more time looking for a nice edition, maybe even splurge if I can afford it. Can't do that with books I know nothing about, it'd be a waste of money if I didn't end up liking it.