Whereas Google Apps is good value as a full service to businesses, $64 per year (UK pricing) per email alias is a bit expensive for this use case.
What would be the most simple replacement for forwarding-only email addresses on your own domains?
If you want to do more complex things, it is quite easy to setup Postfix  on your own server (a little VPS would suffice) to do the redirection, even using a database like MySQL to dynamically create / update the redirections.
In my .procmailrc file in my user directories, I set up forwarding rules. I've set up several servers this way. It's always a bit of head scratching, but it's fun when you get it working and it's not that bad to set up.
What's fun about .procmailrc files is that you can do anything with the email based on regex rules of the subject, to, from, etc. You can even run scripts. I can reboot my server by sending a properly formatted email to a certain email address, for example.