Basically what we need is something very simple but functional.
We just need to integrate Opencart 2.0 in 1 page of our website where there will only be 4 products. Opencart is already installed but we would need someone who can clone our theme, integrating opencart in this small part of the website in order the customers can pay with credit cart.
In order to simplify the job, we will be happy to use the default style of Opencart 2.0 inside of our current theme with minimum modifications. If there is a way to remove the option of customer registration or making the check out in one step page (through extension), it would be great as we have only 4 different product and our customers do not need registration.
Here is a screenshot explaining the basic concept
Our budget is 120 dollars