AdwCleaner and CCleaner are both FREE
⇒ They tell you what is wrong and ask you if you want to fix it and then tell you to register and then you have to pay
It may be true with some software, but not with Xplode's AdwCleaner and Piriform's CCleaner. Is it possible you're confusing "donate" with "pay"? When downloading from the developer's site, or elsewhere (see below), they may ask for a donation. But it's far from mandatory.
• Blue_Zee suggested downloading Xplode's (the developer) AdwCleaner from here:
Note where BleepingComputer states:
For those who wish to help finance the author's work or want to express your gratitude, he is accepting contributions via Paypal. You can contribute by clicking on the following image:
• Another option would be downloading AdwCleaner from the developer's site. How to use AdwCleaner version 3.x includes download instructions, along with a detailed tutorial.
The left-hand side of the page offers the FREE version, while the right side the (paid) PRO version.
Piriform includes 3 download sites. To avoid problems, I suggest using either of these TWO sites.
Hope this clears things up. If not, please don't hesitate to post back and ask.
Best of luck...