My understanding of the marriage bond is that no money was involved. It was a guarantee that no impediments existed. Was seen as prudent when men went fat afield to find wives.
From http://www.legalgenealogist.com/blog/2012/01/25/the-ties-that-bond/
What that bond actually was, then, was a form of guarantee that there wasn’t any legal bar to the marriage. Enforcing the guarantee was a pledge by the groom and a bondsman — usually a relative — to pay a sum of money, usually to the Governor of the State (or colony if earlier, or to the Crown if in Canada6), if and only if it actually turned out that there was some reason the marriage wasn’t legal. The bond shown here, for example, for the marriage of my fourth great grandparents in Wilkes County, North Carolina, in 1816, was a promise by the groom Boston Shew and his brother Simon to pay the Governor of North Carolina five hundred pounds, but it provided that it was “Void on condition that there be no just cause to Obstruct Boston Shew — Intermarriage with Elizabeth Brewer.”7 The use of marriage bonds was common, particularly in southern and mid-Atlantic states, well into the 19th century,8 when most jurisdictions started relying on what the couple said in a written application for a marriage license. And the laws about those… well… that’s a tale for another day…
I'm just wondering why it is also recorded that the father had to mortgage the family grist mill to pay for his son's wedding. We had always assumed that it was for the bond. I guess it is possible that it was for a fancy wedding instead.