This post is divided into three parts, each one dealing with a common misconception about how prayer and blessings work, and about our relationship with God. The one dealing with riches and righteousness is number two, however I recommend that you read each part in order, as I intended each point to build off of each preceding principle.
1) God owes me blessings because I earned them through my own obedience.
This one is tricky because it arises out of a true statement made in D&C 130:20-21 which says:
There is a law, irrevocably decreed in heaven before the foundations of this world, upon which all blessings are predicated—And when we obtain any blessing from God, it is by obedience to that law upon which it is predicated.
This scripture is a fairly straightforward statement that says that if you want to experience the blessings that come from living the law of tithing, or the Word of Wisdom, or Temple worship or any other law of God then you have to be willing to obey that particular principle before you can enjoy said blessing. What this statement DOES NOT say is that God owes us blessings for obedience, whether that be obedience in general or obedience to a particular principle.