One alternative is putting them on-line. But the golden rule is if they have the money and are keen, take the money while they are keen. Which means exchange of some physical item is the best way.

I print directly onto CDs and burn them myself. 0.4 GBP a pop. Plus the CD/DVD burner. But that is mainly because I give them to the people I interview/record with their recordings. And the CD is the more durable medium for printed stuff. The track list goes on paper and I buy CD sleeves with windows - red of course!. Strictly non-commercial, the CD is a thankyou. And given most of those people are oldeish CDs are understood, computers etc are less so.
But CD-R have about the same life as memory sticks. MTBF is maybe 5 years (both), after that you can't guarantee anything.
all 41 hours is on - Stroud Voices, audio history archive