Is it permissible for me to swear by Almighty Allah to do something in exchange for receiving a sum of money?

What is mentioned in the question is considered a promise, and it is recommended to fulfill it according to the majority of scholars (Hanafis, Shafi'is, Hanbalis, and some Malikis). The adopted view among the Malikis is that it is obligatory to fulfill a promise if the promisee, due to that promise, embarks on something that would cause him harm if the promisor reneges; otherwise, fulfilling the promise is recommended.