Looking for books online?

I am wanting to buy some specific books online, I was wanting to know if there was any cheap, older, used, new book websites, where you can buy books and have them mail to you. When I say old I mean from 1985+, the books are mainly romance, like Johanna Lindsey, Cie Edwards, and Diana Palmer. I don't mind paying full price for new books, but if there is a cheap place online to go for older books that would be great. Any suggestions? Or website, besides Amazon?