Shounen Maid Kuuro-kun: Tenshi no Uta

For me, the two best yaoi anime out there. If you want shota rape and a pitiful main character, who falls into a trap and is exploited, then these anime are for you. 

both are about having to do sexual things essentially in exchange for cash or to pay back debts. while okane ga nai has more of a plot to it and more substance, they are essentially the same. SHOTA!! 

Both are explicit shota and both made by Natural High. Though Shounen Maid Kuro-kun is a lot more kinky, they're still pretty similar. 

While Shounen Maid is not the masterpiece that Shounen Maid Kuuro-kun is, both have very similar qualities. For example, both have MC's who are trap characters that work as a boy maid. Furthermore both have a guy takes the MC to his home to work for various plot reasons.