Do I need to pay for root access on Genymotion?

No, root access itself is not a paid extra. In Genymotion Desktop, some Android versions are rooted by default and Android 12+ can be toggled, while on Genymotion SaaS root access is also managed by image/version. How to root a Genymotion virtual device? Root Access

For Genymotion Desktop, Android 5.5–11 images are rooted by default and Android 12+ uses the root toggle. For Genymotion SaaS, Android 9.0 and 8.0 are rooted by default, and other images can be rooted according to the docs.