You can use listing type sponsorship to let people purchase a more eye-catching link, or show them in a special place that regular listings aren't shown.

First, fill out the general settings at the top of Admin Panel -> Revenue -> Sponsorship. You can use any of the three supported payment processors -- PayPal, 2checkout and nochex -- or you can leave all three of those fields blank and process payments manually.

Click the "Add Listing Type Sponsorship Level" link to add a level. Follow the instructions on screen. Note that the item number can be anything unique for paypal or nochex, but for 2checkout it must match the product you set up via the 2checkout interface.

After that, you'll see the levels you've created listed on the sponsorship settings page for you to edit.

If you want to require all listings to be sponsored, just set up sponsorship levels for all the listing types you have.

You can customize the payment buttons and the rest of the payments page at Admin Panel -> Templates -> Manage Templates -> "Sponsor Purchase - Listing Type". You can set the price in the paypal button to whatever value you want, and that amount will be credited to the account on purchase, and deducted at the rate specified by your sponsorship settings. In other words, feel free to have people buy in $100 quantities even if you want to deduct at $1/day.

Prompts asking people to sponsor their listings will automatically appear on the details page, member home and submit listing page.

Notes

To learn how to test paypal using paypal's sandbox with WSN, see this article.