Hi there Josh,
Thanks for getting in touch with us and for you interest in our products 🙂
Event Tickets Plus works with various e-commerce frameworks: WooCommerce, Easy Digital Downloads, WP-Ecommerce or Shopp. Each e-commerce plugin supports various payment method, some of them out of the box some of them via extensions.
For the particular combo you are asking about: Square + WooCommerce, that seems possible with the Square for WooCommerce extension. This should play nicely with our ticketing plugins, as once the tickets are added to the cart the payment is processed entirely by the e-commerce plugin (Woo in this case).
Anyway I suggest you try this out, while we don’t have a trial period, you can go ahead and purchase the products for testing. If you decide they are not what you are looking for, you can ask for a full refund within 30 days of purchase. For more information take a look at our refund policy. WooCommerce has a very similar policy for their extensions.
Please let me know if there’s anything else I can help you with,
Best,
Nico