People at work buy stuff from me all the time but I do not do "orders". I make a few of something, show it off, if they want to buy it they can, what you see is what I have, period. That way I always get my money.
I do get requests to make things, I rarely say yes but if I do, we always settle on a price up front. And it has to be something really simple, inexpensive, not particularly time consuming, and uses very little fabric (I just recently completed 2 neck warmers for a gal using fleece scraps).
I've never not been paid but I've had "slow" payers so I've learned not to be shy with reminders.