You don't really need a Google Apps account for this if you're using Google Domains as your registrar. You can choose to forward whatever email address you want directly via Google Domains.
https://support.google.com/domains/answer/3251241?hl=en
Of course it might involve manually fiddling with MX records if you're using a different registrar for your domain and forwarding (e.g. with Google Apps) might also be required.