That’s what they wanted to charge - Reddit only makes $0.13/user/mo, so their cost must be less than that (or else Reddit has much bigger problems), so let’s say $0.05/user/mo. Apollo has 2 million users, so $1.2 million per year.
Moreover, at that cost, less than a dollar per user per year, Apollo could have instituted a $1/year subscription. But instead Reddit wanted over $100 per user per year, two orders of magnitude more than the cost.
$10m isn't trivial unless your operating costs are in the billions.