You don’t pay a fee per transaction with BigCommerce, because they are actually charged for through your chosen payment processor integrated with the online shop. If you use, say, PayPal on your site built with BigCommerce, you only pay transaction fees to PayPal.
That being said, each Essentials subscription has a threshold for how much you are allowed to make through the online shop. On Standard, you can make up to $50k a year, on Plus it is $150k a year, and Pro includes up to $400k worth of transactions annually. If you accept more than $400k a year on Pro, you can pay an additional $150 a month per additional $200k in online sales.
The plans can be cancelled any time, although refunds cannot be made for subscription payments. There is only a contract for Pro if you have negotiated a special rate for a higher turnover or low average-order value.
All subscriptions include standard features enough to build and run a store online, but the higher the plan, the more tools you get to grow your online sales.
There is also an Enterprise option intended for large businesses. This is completely tailored to the business, with a custom quote, contract and features suitable for large-scale online stores. It is the most complex of all BigCommerce plans, ideally suited for companies with an in-house developer.
There’s a no-commitment 15-day free trial without the need to register your credit card details.