Probably the simplest way is to use a disposable e-mail account that is capable of sending and receiving e-mail. Do a Goggle on disposable e-mail, as there are a lot around. Note that most only receive e-mail.
Another option is to use a free e-mail service to sent up a new account and use a false name (e.g. John Smith). This is useful if you need to subscribe to or sign-up for a service where they need you to reply or send an e-mail to confirm the address, but where you are not sure if they will pass your e-mail on to a 3rd party for marketing.