Chamberlain's myQ garage door openers can be controlled remotely for free, but if you want to access them with a third-party application like the Google Assistant or IFTTT, that'll cost you a nominal fee. Chamberlain is currently offering a number of such subscriptions free of charge for the next two years — no credit card required.
To sign up, just log into your Chamberlain account, click ADD SUBSCRIPTION at the bottom of the page, and choose the one you want. There are subscriptions for the Google Assistant, IFTTT, Alpine Connect, Clare Controls, and EVE for Tesla. You can sign up for as many as you please; they're all free through May 2022. Adding the integrations doesn't require having a credit card on file, but if you do already have one, be aware that your subscription will auto-renew once it's up — so be sure to set a reminder to cancel sometime before that happens.
Whether the functionality Chamberlain is currently offering for free should ever cost a subscription fee is a point of contention; other connected openers offer it for no charge. Still, now's a good time to try it and see for yourself. The services are normally one dollar per month apiece.