Provider of webinars for non-profits?

I am in Canada and am looking for a provider for webinars. We used to
use MyTalkBack(?) But I am looking to see if there are others out there
that we can use.

We produce our own PowerPoint with voice-overs. Then, what we used to
do is just upload the file to MyTalkBack. Then, the thing more or less
work by itself. People go to a particular link, pay for their webinars
and can watch it only once. We were billed some very small amount per
minute.

I've been looking around for some other services, and the couple that I
found all have a very large setup fee. We are a non-profit and don't
have that kind of money to spend.

Can someone advise?

Thanks, Petre