I bought some flowers for my mother for yom tov together with my two brothers, which cost£22. I paid for them and the agreement was I would let my brothers know how much I spent and we would split the cost evenly. Being that they cost £22 we each should pay £7.33.
One brother paid me back £7.30 of which I am obviously happy to let the extra 3 pence go and the other paid back £7.50.
Is any of the above a problem of ribis. Should I return the extra that my second brother paid me and refund him so that he only paid 7.33?
Thank you for your question.
It is not an issue of Ribis, and you do not have to be concerned that your brother gave you Ribis. The reason he gave you extra little bit is not because he got a “loan” from you, rather either to thank you for getting the flowers for your mother, or because he is not makpid on a few pence that he is giving his brother.
Halichos Yisroel Chapter 1-21, Poskim.