There uss a system to generate a Temporary email for instance http://www.tempemail.net/
which allows you to create just that - a temporary email - you can use it for reasons such as you describe where you don't want to give out your real address. From what I cam remember you can ask for emails to be sent to your real address that remains anonymous
It isn't very secure - I used it ages ago - you just make up an email address but at that time someone else could end up with the same address and have access to your messages so it really not for receiving anything that you wouldn't want to get in someone else's hands but maybe that has changed.
If you Google temporary email it will come up with a number of these services.