Ouji to Kotori(2007)

Ouji to Kotori

Poor art school student Suzuki Keiichi wakes up one day to find himself as part of an auction in some desert land he knows nothing about as a way to pay off his debts. He has no idea what's happened to him until he's suddenly bought by a man he's never seen in a language he doesn't understand. He's terrified, and it turns out the man is a prince who bought him to be the servant of his younger brother. Every day he plots a way to escape from this unknown land, but he finds himself slowly captivated by the prince's charms.

Yamanaka Hiko's hit tankoubon. Book also contains an unrelated oneshot "Sabishisa no Nedan".