How to know that she is cheap

She is always flattered by every word a guy tells her.

I'll answer this question on the assumption that the definition here for "cheap" pardon me, and crudely put, a "whore/slut" i.e. lacking in the decency to "keep her clothes on".
I thought the answer to this question is actually really easy. As a girl,
there is really only one "test":-
If the girl is able to get into bed with you really easily, you can imagine that she gets into another man's bed as easily, if all she ever demands is nothing but money
(either for card or others), if she hardly feel comfortable with what she gets from you but plays around and feel comfortable with other folks, my friend she might be playing on the path of being cheap. Even if she may have fallen in love with a man at first sight, a decent girl would still find that it is a whole lot separate issue to share her physical intimacy that easily or quickly. I do like to point out though that girls that dress in revealing clothes may not necessarily be cheap. She may just like the attention she gets; she is dressing for her man, but it does not mean that she is going to sleep with every man.

Partying is always her hobby.

   I'll point out one other thing:
I'm guessing that you would like to avoid getting involved with women who have had many sexual partners. An extremely ineffective way to find out if a woman has had many sexual partners is to let her know that you will judge her if she has. If she can sense a hint of judgment about you, she'll be a lot more likely to lie to you. So you'll be shooting yourself in the foot if you don't drop this mean attitude.Well, don't be too attached with ladies who seem to be addicted to make up, money, bags,chewing gum, a lady who also demands too much, the nature of being cheap might be flowing through her veins.
   A better way to find out such things about a woman is to be nonjudgmental when the topic comes up and then, before perhaps asking for an outright number (if you really, really need to know it), simply ask her what her sexual values are. Ask her kindly what her beliefs are about when sex should be had, and how she implements those beliefs in her own life. If what she says turns you off, then you don't even need to move on to asking the number. You'll already know you two aren't right for each other.

Having sex on your meeting, she can do likewise to someone else.

There's nothing wrong with wanting a partner who has the same sexual values as you do. There is, however, a whole lot wrong with being mean about women who don't share your sexual values.
And if you've got a double standard -- if you think men can have lots of partners and it's fine, but women can't or else they're cheap -- then that's a whole other story. It means you're a hypocrite. Being mean and hypocritical reflects poorly on a person's character.