To add to what Mike Yates just explained:

I stated in my first post that Sharp did pay singers cash, at least during the first Appalachian trip, which is the only one for which I was able to find figures. The amounts ranged up to $5 (the online calculator I used at the time estimated that at $100 in today's values), and seem to be have been graded to some extent according to the number of songs Sharp collected - so Mary Sands, his first seriously good informant, got the full $5. Surprisingly, he paid the same amount to the locally-famous ballad singer William Riley Shelton ('Frizzly Bill'), despite rating him a poor singer who couldn't stay in tune or remember his words. All became clear when I found a letter in the Campbell archives explaining that Frizzly had later confessed to having drunk an entire bottle of moonshine on his way to meeting Sharp!

In addition to those payments and the other gifts I listed, there was the well-documented assistance to the Hensley family to pay their daughter's expenses on starting school at 13 (some of which came out of Maud Karpeles' own pocket). When Maud returned to the mountains 32 years later, the daughter, Emma, greeted her like a long-lost bosom friend, and asked could she please have another copy of Sharp's song book, as the community had worn out the old one.

I don't know whether he paid any singers in England, though the gift of a concertina to Louie Hooper is well-known. It was in the museum at Taunton. last time I looked.

Thanks Derek for that clarification regarding Evelyn Sharp. I'd trust Derek over Wiki every time.