It depends really. It terms of formation it doesn't break any rules but I wouldn't call it particularly clean and tidy English. First of all, I'd be more specific - change the "it" term to the actual object and to make it easier on the eye I'd say "When you do such and such, how much do you collect?".
In addition to the anonymous comments above, remember that capital letters and punctuation is important in English. Your sentence won't be correct if you don't have those elements.