If you want mailslam.com I'll transfer it to you. I was going to build something similar but in reality I'll never get around to it.
Please make a show HN when you launch it. Iām currently a Sendy user but would love to find alternatives especially if they are not in PHP.
alphamail. electronilist. bullhorn. campaignking. untitledlist1. goodmail. emailotron. quicklist. emailist. senditall. postbag. carrierwave. deliverist. droplist. notspam. relimail. emailblast. firstcontact.
mailchamp
Anzee. Build integrations so you could have a Mailchimp-anzee setup. If it's a company you're starting, think about the headlines: "Mailchimp-anzee merger".
Option 2:
"Howler". Since it blasts campaigns, campaigns are "howls" instead of "campaigns".
Also: Howler is a monkey that lives in the Amazon. Since you mentioned Amazon Web Services integration. It's a twist on mailchimp and AWS.
If we want to be a bit douchey, we could drop some letters to get Howlr or Hwlr.
Option 3:
"Hermes", who is the "the herald of the gods, as well as the protector of human heralds, travellers, thieves,[1] merchants, and orators."
Your users are the gods. The fact it sends messages for a fraction of the cost plays on merchants/thieves/travellers having a tight relation with money.
If not Hermes, then "Augur". Again, douchey: "Augr" or "Ogur".
Option 4:
"Colporteur" or "Colport": A colporteur is a peddler. A seller who goes around small villages or isolated places[your software reaches even the most isolated people] and screams to villagers or a place's inhabitants what's to sell/buy. Typically, the inhabitants, hearing the colporter's cries will go down and haggle/trade, buy or sell. These "screams" have a certain "rythm" and aren't disagreeable, which you can use as a metaphor for a "campaign" in your software.
Also known as a "Hawker", apparently from the Wikipedia entry.