Which service to use if you intent to primarily collect payments under 3$? Needs to be able to collect payments from all over the world, not just the US.
In Europe, the answer is probably GoCardless. Depends what kind of payments though - if it's card type payments you need, (I.e instant, fore commerce type stuff), then not, but subscriptions, most bills/invoices, absolutely GoCardless.
Why? Their rate is 3.9% + €0.35 for non-european merchants and 2.9% + €0.25 for european merchants.
That's not exactly cheap. Do they offer a service I don't know about that makes them better suited for small payments than Stripe, Balanced or BrainTree?
I didn't know about their high fees. But I know they have a good international money transfer support. I used them for personal financial transactions for 4 years and found them very good.