Mozilla launched Firefox Relay as a free product that gives you five email aliases you can use every time you need to sign up for a random account online. Now, the organization has introduced a paid Premium tier for the service that will give you access to even more aliases. You'll get your own subdomain (yourdomain.mozmail.com) when you subscribe, and you'll be able to create an unlimited number of emails. The tier will also give you access to a summary dashboard with the emails you make, the option to use your aliases when you reply to messages and a 150 kb attachment allowance.
After you sign up for Relay or log in with your Firefox account, you can generate an alias even on another browser like Chrome or on mobile. If you use Firefox and install the Relay extension, though, a Relay icon will appear on the entry field every time you visit a website that asks for an email address. You can simply click it to generate an alias. The service will forward messages you get using your aliases to your primary email account, and you can block all messages from coming in or even delete the alias when it starts getting spam.
In its announcement, Mozilla said it decided to introduce the paid option because lot of beta testers wanted more than just five aliases. It didn't say how much a Premium subscription will cost in the future, but it's offering the tier at an introductory price of $1/EUR1 per month for a limited time. At the moment, the option is only available in Canada, United States, United Kingdom, Malaysia, Singapore, New Zealand, Austria, Belgium, France, Germany, Ireland, the Netherlands, Spain and Switzerland.
Update 11/16/21 12PM ET: Clarified that you can use Relay even on another browser and the extension isn't necessary.