I appreciate the test months Spotify has, but the implementation just threw me in a bad UX loop.
Because I already used my bank account for Spotify once, it threw me a "you already used a similar offer" error upon payment. This is fine of course, but it prevented me completely from subscribing to Spotify at all.
I contacted support, who was very helpful (Greetings!) and provided me a no-trial link which worked. It only worked for standard pricing though, not for the student discount option. So the helpdesk person worked me through the normal abo process, then through the student application process and then gifted me an extra month because the student discount would only kick in upon next month.
All this struggle could be solved by a discrete link tag and two explainatory sentences, no? If you implement this into the error thrown when the offer was already used, there is no potential to confuse user either.
At least a help page in the FAQ would be appropiate I think.