Guys I don't love ABEM but the fee structure and module cost is pretty straight forward--
@Mount Asclepius has it correct upthread.
You pay one annual fee. Its $330/year. Its Netflix. You can do ALL THE TESTS AND MODULES YOU WANT, and they are included in that fee. If you want category one certified CME, they tag you for 20-30 extra dollars on top when you take a module, but leave this optional if you don't need/want said (cheap but not free!) category one CME. I guess I prefer this, if it keeps the annual fee lower to leave it a la carte.
While you pay an annual fee, our board certification is on a 5 year cycle, so some tasks must be completed every 5 years. Specifically you need to do 4 of these module multiple choice tests within the 5 year period, and you need to attest to an activity, and maintain your medical license per their standard. And pay your annual fee. If you do THAT, you stay certified. So every 5 years you are paying them a total of $1650, taking four open book online 50 questions tests, and clicking a handful of boxes.
Now it was SLIGHTLY more complex when they rolled this out, as there previously had been a 10 year cycle and people were at various times within said cycles, so to make it financially fair, they allowed different cohorts to pay for single one-off modules, etc. But they did push out numbers and explanations of this, and no one cohort took a financial bath changing over.
Now, do I want to pay $330/year for what I find to be a rather silly but occasionally insightful open book multiple choice test that I can bang out in 20 minutes? Nah. Not really. But I honestly prefer it to taking a q10yr high stakes single-take exam for a similar price, and I find them a modest improvement on the prior LLSA tests...