Scoundrel for Sale by Courtney McCaskill

Four years later, Gabe has inherited his great-uncle’s estate, and along with it, his great-uncle’s astronomical debts. He needs to marry an heiress, but there isn’t time to find one. If he can’t produce five hundred pounds immediately, his great-uncle’s creditors are going to seize everything, including his poor great-aunt’s wedding ring.

A scandalous solution…
Gabe can only think of one way to come up with the blunt: put himself up for sale in London’s most notorious bachelor auction. He’ll have to spend the night pleasuring the highest bidder… no matter who it might be.
But what will Gabe do when the unthinkable comes to pass, and the winner of his auction is Abigail, Hart’s now-widowed little sister? It’s his worst nightmare… but also his dream come true. What’s a notorious rake to do?