Buying a new US Number is actually pretty strick, for the seller they will need to give his ID for verification purposes.
There's no guarantee that this Paypal account are going to be used for something acceptable by Paypal TOS.
Hence, why it is risky.

You can get your own Number through Skype
https://support.skype.com/en/faq/FA256/how-do-i-get-a-skype-number