Creating my own donation form

Hello,

I am looking into building my own donation form that will be hosted on WordPress that anybody can access and make donations on. I am currently trying an implementation using BBMS payments API but it seems that the payments API requires authorization to be able to use. Since the donors will not have a login for authorization, it seems that this may be the wrong API to be using.

Is there another API I should be looking at? Or am I approaching the BBMS payments API incorrectly?

Thanks,
Kevin