"Yes, that happened to me. Summoners and their daeva can renegotiate payment on the fly as long as they come to an agreement, so faced with someone who literally just wanted food to give to the needy and couldn't think of anything to trade for it - well, I didn't want her to summon more demons until she found one who'd go through with it, the poor girl, so I made all the food and then just sort of stared at her until she asked if I might have remembered I left the stove on in which case I could have one of the nectarines and call it good. And then it was 'yes summoner' and that was that."