I say $5
$5 is to low as a price.If you don't like the painting at least you should appreciate the work and the time spend to create it.
I think its matter of the persons appreciation of art, like you mentioned.
Atleast he/she threw an offer, it may not be a good one, but still an offer. They may not like it, but who cares the person got a ton of offers already at idea price range.