I'm not sure from reading your post whether or not the person asking was asking you to make them for free. If you don't mind making them (for a charge)
I'd just tell them to give you $_____.00 and you'd be happy to.
I did some extensive genealogy research a couple of years ago and my sister in law told one of her friends about it. The friend asked if I would do one line of her family for her. I told her yes, I'd be happy to if she would send me a check for $100.00 to get started. I never got the check----I never did the work!
Easy peasy.
Roxanne