Be aware of of spamming nightmares, you may be bombarded with them. Keep few opints in mind before you start up email balst:

only e-mail out to existing customers - people who have bought from me before. and if someone e-mails me back to take them off the mailing list, i comply.

Do not buy emailing list as it may be of poor quality, absence of permission i.e. Even if the data is accurate, this in no way means these people want to hear from your client.

The email blast is very effective only if you are sending an email blasts to a group of people that willingly gave you their email address and contact information. Go for companies that offers opt-in email marketing services .