Welcome! Good to have you here!
To add to @lwebb’s incredibly detailed information, there is also a thread where we discuss other free stories and @SweetAIBelle is posting links to YouTube videos of full Classic serials available for free there
Stories available for FREE (Doctor Who and the Whoniverse)
As for recommendations for audios, if you love the Eleventh Doctor then you could try The Eleventh Doctor Chronicles with the companion Valarie. It’s one of the highest rated series on the site!
Here is a thread about it
The Eleventh Doctor Chronicles
The trailer:
I hope you enjoy the site and look forward to hearing more from you!