If you're willing to risk going over a vague TOS restriction (no "excessive" usage), try fusemail.com. If you want to pay for certainty, some standard SMTP ser

If you're willing to risk going over a vague TOS restriction (no "excessive" usage), try fusemail.com. If you want to pay for certainty, some standard SMTP services are: Sendgrid, AuthSMTP, fastmail.fm.