You can set DJ-Classifieds to use Points/Credits only. With this feature enabled users can use only Points to pay for certain (paid) actions in DJ-Classifieds.
Now you can let your users pay once for Points Package and then use Points as regular currency for all paid DJ-Classifieds actions.
You can set the exchange rate you want. For example, 1 Points can be $1 or less or more - it is up to you!
You can set the price in Points for every element that user is charged.
Learn more about Points system here.
Setting up DJ-Classifieds to work with Points only is easy.
First, go to Components -> DJ-Classifieds -> Options -> Use 'Points packages' setting and set it to: Yes - only points payments and save settings.
Now the magic happens. With this one setting, you changed the way DJ-Classifieds operates.
Now every action that needs payment is done in points only, and the only way for the user to get points is to purchase Points Package (you can learn more from this tutorial: creating points packages in DJ-Classifieds).
The Points Package purchase is the only place where the user can use the "regular" money now using any payment method enabled on your site.
That is it
Now you have disabled regular prices for all of the paid elements and only prices in Points are visible to your users.
This feature is available and works with DJ-Classifieds version 3.6.2