Yep. I have 4 retainers. Only 2 free, the other two I have to pay for. You can pay for up to 7 more right now, for a total of 9, and once the app comes out, you can pay $5 so you an spend another $2 to hire a 10th retainer.

Yes, you now need to pay microtransactions just so you can buy more microtransactions.