You need an email address that is EXPENDABLE. the sub accounts available with commercial services are ideal. free email addresses will do, but these often prompt for an email address, which will itself generate spam. Then every time someone with no excuse to ask for an email address asks, give them the spam magnet. Free email addresses can be left to fill with spam and die on the vine . Sub Accounts can be routinely cancelled and replaced with a fresh magnet as they fill.