I don't know if anyone has made this suggestion.

Get the email addresses of everyone who attends your club, and then go to other clubs and collect the email addresses of attendees (with the permission of the organisers), this is easily done by passing a clipboard around. Then email everyone on a regular basis with information about your club events and a pointer to your web site.
Give everyone an opt-out opportunity.
This has to be the cheapest way to advertise your events. It's free.

Just a thought

All the Best

Alan