When you receive a payment regardless of the funding source paypal charges you 2.9% + $.30 for processing the payment.
As you will be using an invoice, this is considered a sales transaction and fees are applied.
If someone sends you funds using the Send Money feature, there are no fees unless the sender uses a credit card. Then either you or the sender pays the fees. That's between you and the sender.
Where you run into a gray zone is that the purpose is to collect rent. Technically this is considered a service as you are doing business and you should use the invoice method as you will have proof of payment for your records and tax purposes.
One the other hand, the Send Money feature could be used, however, it's quite possible PayPal could see the pattern and possibly block or limit your account as you're using a feature not intended to be used that way.
It's your choice. The downside of either method is that you are not covered for Seller Protection under the User Agreement because the exchange is considered a service.
Personally, I would just have the tennat pay with a check or cash. You don't need PayPal to collect rent.
