Friends make the worst customers, the worst borrowers and the worst "I freely give this to you" people in the world.
What ever issues come up, it's your fault, and you knew about it...
You will never see your loaned money again...
They always want what was given to you back again at some point in time... especially AFTER you have sold it.
Hypothetically, avoid selling to friends at all cost... chances are, they already know someone else who is looking for that thing you are selling... and willing to pay more than what you want, just maybe at a later date.
And why give them a "deal"? Other than putting up with you (that's funny and you know it) what have they done to deserve a deal?
I don't use "friend" nearly as much as I use co-worker (you are sadly mistaken if you think co-workers are your friends), relatives or an acquaintance.
An example... a friend of 20+ years "borrowed" $700 from me... that was over a year ago now... He now has a new car, a nice apartment and oh yeah, a new phone - the latest Nexus who gives a crap phone.
Am I mad - nope... 100% expected getting screwed over when I "loaned" him the money. The WORST part is $20 a week and it would have been paid back months ago...
Good luck with your hypothetical... if it's already happened let it go and keep your "friend" at arms length from now on...