I'd pay $20 to see most folks too, however, there seems to be a price point break in what people can, or will pay. We had a Juno award winner here (whose name I won't mention in this public forum as I do not have permission), who rarely performs solo, is well known to everyone in music in BC. So we thought let's get him top dollar. We sold tickets at $20. The first dozen or so were gone in hours, but we only had half a house.
Next time he came we charged our usual $12, and packed the place to the rafters.
One problem we have found with house concerts is that just because a performer plays house concerts does not mean they are on the skids. So when David Essig wanted to come and visit for the weekend and we put on a concert the reaciton was, "David Essig"? at Pioneer Ranch? no way." Couldn't believe it. We even pulled in one travelling salesman who heard about it and couldn't believe his good luck.
This is not so much a problem now but was at the beginning, so needs to be addressed in the promo material. We used the idea, passed on by a performer, that they were tired of playing "insdustrial strength" festivals. Wanted a intimate listening audience.
In reality of course, the other reason is that often the expenses are so low, (no sound system usualyy, no hall rental, no band,etc.) that they make as much as at some top gigs.
By the way, we have always been acoustic. On two or three ocassions we have added a simple mic just to balance voices or insturments.
Oh, and we take the approach that "a bum is a bum" --which means kids pay unless they sit on knees or are regulars.