Started talking to Jensine or whatever she is called, and entered the zone where I can joke/boost, etc. However I can not exit it. Made the timer run out and I still can't do anything. What the hell?

The Persuasion minigame makes you select four different actions of conversation, and some NPCs will like some more than others. Try to get the more powerful marks on the ones they like, and the least powerful ones on the ones they dislike. Once you've selected all four, you can try again or quit.

That's not the problem, I did that for a while. I just want to leave. Every option is blocked and I'm all out of coin, didn't even access her inventory.

Usually you just press 'done', once the minigame is over. Unless you have some kind of weird bug...but that doesn't sound right.

Also, you said you were 'confused with bartering' -- bartering, or haggling is when you open up that little slider bar to change prices. Persuasion minigame is the four-quadrant thing.

See the http://uesp.net/wiki/Oblivion:Speechcraft#Persuasion_Guide.

Well, I can't click "done". Guess I have to reload.

Huh. Are you on PC or XBox?

Playstation 3.

Hm, well in that case, I'm afraid that you'll just have to reload.

Don't worry -- the game autosaves every time you enter a building, so your last save will be when you entered her shop (hopefully).

Yes, I noticed, quite lucky. Tried it again on a character outside (saved first), but I got stuck this time as well. Quite weird. The "done" option just isn't available, and is shown shaded.

Edit: Oh, and lol at "consused"

Even if the disposition is at ZERO, you must choose an option to exit. That is, each of the choices, must be clicked, in order to exit the mini-game. What matters is the order in which you make your choices. It takes a bit, but after I got used to the game, I can get someone's disposition up in about 5 seconds.
I put the smallest wedges in the worst choices, and no matter if it is a zero wedge or not, whatever is left over after my bad choices, is placed in the good choices. You will never lower disposition this way.
Though I lower certain people's dispositions for my roleplay.

Man i know how you feel. The ps3 unfortunately is the buggiest platform for Oblivion and this happened to me too. You just have to reload the game Sorry man