While no one is certain of the origins of this tradition, I remember it from when I was a child in the low country of South Carolina.
We lived inland on the fertile coastal plains along with a healthy population of what can only be described as "traditional" people. Far from the typical portrayal of these communities, they were often a gumbo of various cultures simmered together over generations.
The practice of giving wish or blessing dolls no doubt has roots in several cultures. The Slaves brought their traditions from Africa, the Acadia had similar traditions they no doubt deposited as they skipped the coast before eventually landing in Louisiana. We also know of a german custom of blessing dolls made from natural local materials given as adorned with $ or personal notes of well wishes.
Some areas also give small burlap "sacs" of corn, but updated with more modern cash pinned to the bag.
Anyway you do it, a neat idea, and many generations have done it before you!