I'll say "yeah, I usually charge $X for that, when can you work on it with me/when would you like that done?" If they're willing to pay for it, it shows that i

I'll say "yeah, I usually charge $X for that, when can you work on it with me/when would you like that done?" If they're willing to pay for it, it shows that it's actually a legitimate help to them. If not, it saves my time.