You can donate any amount in pounds sterling - your bank will convert your currency automatically. (Donating in sterling gives me a better net after the processing commissions.)
There are many costs involved in producing these broadcasts and podcasts, and any stations which broadcast my shows do not pay anything for them. It also takes a great deal of dedicated effort to produce such programmes. If you enjoy these shows, please give as generously as you can to support the continued work to publicise this art-form.