Hi Ganibal,
Availability of ads are depends on which type of advertisement you are creating it, it means - Ad type + Per Credits Requirements = Per click you will get it. You can try by yourself after creating a new add, and can check each credits requirements for per click, let me show here one example with cheapest add you can make -
So, if you create a ABP Mini Ads which per click ads are for 0.001$, so for this ads, you will get 200 Credits = 200 Clicks