Bizarre comedy disguised as something else. Humans are being transported to Equestria through no fault of their own. The only polite thing to do is to help them settle in, and that includes trading in their old money for Equestrian bits.
The trouble with Sunset's 'Flanksy' graffiti art is, vandalism doesn't belong to the artist. So Twilight comes up with a scheme to sell things you don't own and don't have. It uses computers and the interneight!