Not the OP, but a .com domain costs me about $12/yr and fastmail.com costs me about $50/yr and I get unlimited email addresses as a result (catch-all).
Not the commenter, but cloudflare email routing works well w/ a $1/year xyz domain (random 6 -9 digit domains are discounted). It's worth noting that this might not be as private as iCloud or mozilla's solutions, as you share a domain with all other costumers. On the other hand, people have held onto domains for very long amounts of time, and the system is less susceptible to "it wasn't making enough money so you can't access some of your accounts now".