Mark when you're free and send the link. No sign-up, nothing saved. Your times live inside the link.
Send this link. Anyone who opens it sees your free times, view only.
beetSlots keeps no database. The meeting name, your name, time zone and every free slot are packed into the link. If you lose the link, the calendar is gone, so keep a copy.
beetSlots is a free tool from Beet Labs. Find more simple, no-sign-up tools at beetlabs.co.