This is much better than Christianity....
Read your bible. Jacob bought his wife for 7 years labor. But his father-in-law cheated him by substituting the older, not so pretty sister of the woman he wanted. But, then he offered up a deal and threw in the one Jacob wanted as a second wife for seven more years of labor.
Read on a few more books and David bought his first wife from Saul. At first David thought he could not afford her, but Saul said "lets make a deal" and set the price at 100 foreskins from Philistines. Not wanting to be a cheapskate, David paid him 200.
Of course that is Judaism, but if it was good enough for the Old Testament patriarchs it is good enough for modern Christians.