UC Node Checkout for pay to publish user content? Is there a way to use this module for a pay to publish set up, like in classifieds where user adds content and then pays to publish it in D7?

Generally speaking that is....I like many others having been paying for a module but the person who created it has disappeared now and it is first time ever I've paid for something re drupal. Normally I study up on anything open source- which just goes to show there are no shortcuts in this world.
Try Pay-per-node

This module allows creation of a number of nodes of chosen type for some users. It temporarily overrides the node creation permissions and keeps track of the number of nodes the user can create.

It can be used as standalone module or as an e-commerce plug-in. In the second case paypernode can be integrated with Ubercart, providing a new "product feature" which will allow, upon product purchase, to create a number of nodes.