You don't pay for any of the Android stuff, you pay for a device which can run it and then you get it. Sure, you can easily pay for software, but you're not paying for the basic functionality. All of that is gratis. At worst you go to goo and get the gapps for your device, and maybe twiddle build.prop such that you can actually use the store, and then google will happily treat you the same as any other user.
Since you're not paying for Android, Android is not a consumer product. It's not like Windows where you can get it free or you can pay for it; you can only get it free. Perhaps there's some for-pay Android-on-PC efforts by now, I'm not sure. But community replacements for official software stacks are generally donationware and nobody has harassed me for money yet.