Does anyone one think that santana is kinda a bitch cuase of the things she said to Finn after they had sex. And why do did Finn and the other girl lie top each other the next day

Not really... I mean - of course it was kinda mean, but I suppose that EXACTLY what he could've expected. He knew why she did it ("win-win" for her), and it's obvious you won't respect a guy who has sex with you just to lose "the big V". I think she just treated him like he deserved for making the deal. He was pathetic. Not offence to Santana, but for Finn it was just like visiting a prostitute. But cheaper. At least he had to pay for the food.
I think the next day he understood how stupid he was, so he lied about it, just because he was teribly ashamed. It was a sing he'd like to take it back.