99% of paper books I buy, I buy new. I'll occasionally buy an E-book if the paper book is out of print. I do like going to used bookstore, but more as a treasure hunt - finding a long forgotten fave, getting a spare copy of a good book for a friend and occasionally finding something worthwhile.
I don't have many other hobbies, and I'm not out much, so I can justify the expense, though I do get ticked off at the higher cost of books here in Canada compared to in the States. Online orders don't help because they get you at the border. I once ordered some non book items from Amazon US. They cost me 27$,, the brokerage,, taxes and duty cost 45$. That's the last time I'll do that.
Every time I visit the U.S. I look for bookstores, but they've all seem to have disappeared. I was in Orlando Fld. in November. I found 1 bookstore in a mall - the mall was empty (and creepy) and the bookstore was holding a going out of business sale. I think there was 1 shelf of SF/Fantasy. Very sad.