update: mention anonymous payment methods for SimpleLogin and addy.io

docs/email-aliasing.md

@@ -61,7 +61,9 @@ Using an aliasing service requires trusting both your email provider and your al
 
 </div>
 
-The number of shared aliases (which end in a shared domain like @addy.io) that you can create is limited to 10 on addy.io's free plan, 50 on their $1/month plan and unlimited on the $4/month plan (billed $3 for a year). You can create unlimited standard aliases which end in a domain like @[username].addy.io or a custom domain on paid plans. However, as previously mentioned, this can be detrimental to privacy because people can trivially tie your standard aliases together based on the domain name alone. They are useful where a shared domain might be blocked by a service. Securitum [audited](https://addy.io/blog/addy-io-passes-independent-security-audit) addy.io in September 2023 and no significant vulnerabilities [were identified](https://addy.io/addy-io-security-audit.pdf).
+The number of shared aliases (which end in a shared domain like @addy.io) that you can create is limited to 10 on addy.io's free plan, 50 on their $1/month plan and unlimited on the $4/month plan (billed $3 for a year). They accept [cryptocurrency](https://addy.io/help/subscribing-with-cryptocurrency/) as payment or you can purchase a voucher code from [ProxyStore](https://addy.io/help/voucher-codes/), their official reseller.
+
+You can create unlimited standard aliases which end in a domain like @[username].addy.io or a custom domain on paid plans. However, as previously mentioned, this can be detrimental to privacy because people can trivially tie your standard aliases together based on the domain name alone. They are useful where a shared domain might be blocked by a service. Securitum [audited](https://addy.io/blog/addy-io-passes-independent-security-audit) addy.io in September 2023 and no significant vulnerabilities [were identified](https://addy.io/addy-io-security-audit.pdf).
 
 Notable free features:
 
@@ -103,6 +105,8 @@ If you cancel your subscription, you will still enjoy the features of your paid
 
 SimpleLogin was [acquired by Proton AG](https://proton.me/news/proton-and-simplelogin-join-forces) as of April 8, 2022. If you use Proton Mail for your primary mailbox, SimpleLogin is a great choice. As both products are now owned by the same company you now only have to trust a single entity. We also expect that SimpleLogin will be more tightly integrated with Proton's offerings in the future. SimpleLogin continues to support forwarding to any email provider of your choosing. Securitum [audited](https://simplelogin.io/blog/security-audit) SimpleLogin in early 2022 and all issues [were addressed](https://simplelogin.io/audit2022/web.pdf).
 
+You can purchase SimpleLogin anonymously via their official reseller, [ProxyStore](https://simplelogin.io/faq/).
+
 You can link your SimpleLogin account in the settings with your Proton account. If you have the Proton Unlimited plan or any multi-user Proton plan, you will have SimpleLogin Premium for free.
 
 Notable free features: