Only if you want to be able to accept online payments. It is possible just to use the system to quote and book jobs and arrange payment separately.
We now integrate with WooCommerce so you can use any WooCommerce payment gateway not just PayPal for processing credit card transactions.
To find an online payment provider please see the WooCommerce payment gateways list and choose one that operates in your area of the world.
WooCommerce Payment Gateways Page