Two Hetzner CPX31 boxes sounds like it'd do just fine here too, providing the redundancy you mention for a fraction of the cost. Or get the boxes from different companies, for the same sort of overall price.

Yes some of the other tools could arguably be worth paying for, but if the author's concern is that he's short on money and $140 is a lot, why didn't they KISS and only use what they need? Then scale as and when needed in the future.

Y'know, do what HN regularly preaches?