What I did was... this girl I've known for a few months now wanted to hang out, and also wanted me to buy something really expensive for her. Well, I knew what she would do to convince me, but I actually have fallen for a real love, someone who I think about in a long-term context, even though I haven't actually talked to her.
So, I told this other girl I didn't want to hang out. I spent the whole weekend alone, and when I realized how juvenile this was I frantically called her non-stop Sunday night until she answered, and we hung out Tuesday. She doesn't love me, and I have grown estranged from her, but she'll get friendly with me when she needs something, like clockwork. Applaud a lonely guy like me for actually seeing this, and recognizing the hollow nature of it, and being unsatisfied with that. A phone call from a girl that I like, that actually likes me, is better than all of the one night stands in the world. They don't have much longterm meaning, unless you're talking about an STD.
Anyway back on topic, I don't supposed I really turned a girl down for it, as the reason she would get with me wouldn't be out of lust or love, but something else... Oh, and I didn't stick to my guns anyway and called her up eventually, giving in to loneliness and a bit of lust.