Unfortunately I know little about the process for actually applying for a merchant account or where to get it from. That's what the ISO we partnered with handle

Unfortunately I know little about the process for actually applying for a merchant account or where to get it from. That's what the ISO we partnered with handled. Also it was "high risk" accounts (cough adult cough), that is different banks than you'd be using. Same with the competitor payment processors I'm aware of. If you're unfamiliar with the process and can't find a bank to walk you through it, an ISO is not a bad idea. They'll walk you through the process and help you find a bank, and also a processing gateway. They'll also add a margin on the processing fee, but it's not a big one, and certainly less than paypal or stripe. For processors starting out, there's nothing wrong with using Stripe or Paypal etc. When you ramp up to using your own Merchant Account, Authorize.net isn't too bad as long as you're not doing recurring payments (those get tricky), or maybe even Rocketgate.