Is it possible to offer a course where the first say 20 people receive the course for free?
Is there a limit to configure please?
The best way to handle this would be to create a coupon code for 100% off your course pricing - you can set a limit on the number of times a coupon code can be used so that it can only be used up to 20 times. More on that here.
Once the coupon code has been applied to take the price to $0, no credit card will be required to finish the signup :)
For example, our organization has Sustaining Subscribers who will be offered this initial course free of charge. Do I create one coupon (assuming I can give it a name?) and then simply give each Sustaining Subscriber the coupon that applies to that one course? Does the Coupon have to have a time limit? Hopefully there will be more and more Sustaining Subscribers sign up so part of what they receive will be this free training and it should be valid for a long period.
Is there any downside to offering a coupon this way? Those who are not Sustaining Subscribers would not be given the coupon. Is there any way of tracking who uses the coupon to make sure the coupon number is not being shared with those who are not Sustaining Subscribers?
Yes you could create one coupon (with a name) and give it out to multiple people. There's no need to set a time limit on the coupon - that's only for people running time-limited pricing discounts. If you need to make sure that users have long term access to the course, when setting your pricing be sure not to include an expiry date (or set one that's far into the future if that's what you'd prefer)
And yes you will be able to see which users signed up using the coupon code from the Orders page of your admin dashboard.
And happy to help if you have any further questions at all.