I last took this over 3 years ago so not sure how useful what I have to say is (given that obviously that whole section of my life is a little hazy/clouded in denial).
Personally, I did find it worked quickly - a lot quicker than the doc had led me to believe. Not sure if that's just because I had started on a higher dose than I should have, or because I had not taken a drug of that type before, or some other thing.
I did not get on too well with it to be completely honest. I found it was very good at controlling my impulsivity and what I like to term 'nervous chatter', but as cliched as this sounds I really did feel quite 'spaced out'. Not in the sense that I did not feel like 'me', but more that I was underwater or a bit detatched from my surroundings? I found I would sit still for long periods of time almost like my brain couldn't give my limbs the right instructions to move (not that this was actually true, obviously, it just felt that way).
However, none of that should put you off. The actual reason I stopped taking it was because of it decreasing the effectiveness of the pill (yeah, my clever psych didn't bother telling me that or actually looking at my medical records, it would appear) rather than the above effects. Cus as I say, I coudn't honestly say how much of that was the medication and how much was just 'me'. I have heard others have really good positive experiences with it - so who knows, if I'd stuck with it then it may have helped me too. And as I said, it really did curb the impulsivity side of things for me so I'd say from the whole money wasting side of things it could really help calm things down for you.
Sorry for the ramble, hope some of that makes some sort of sense!