I have a project that I believe requires a custom payment solution. We aren't sure which payment API should be used, but we are looking to hire someone who can build out a checkout & payment processing flow that is minimally intrusive. The lynchpin of the entire business model is the ability to provide a 7 day free trial (with credit card details provided) and charge the user if they don't cancel within the trial period. We haven't found a plug & play solution for this particular problem.
The product being offered is an online course so perhaps there is a WordPress plugin designed specifically for this that would resolve the need for a custom API implementation, but we haven't been able to find it.