Here's the deal...
Free is good. Let's get that out of the way. There are good "free" sites, and this is one of them.
Paying is also good, when value is => cost. This can be subjective, but usually not. An illstration:Linux is excellent software, and in most cases, "free." Windows XP Pro is excellent (objective opinion here) software, and is clearly "NOT" free. Depending on what the use is for, and how productive you expect to be, will and should be your determining factor in which choice will be more beneficial to you. For example, the cost of re-training a workgroup to navigate linux, after this group is already proficient with windows must be taken into consideration, as well as the expected future enhanced productivity. A very hard task to accomplish and companies wrestle with this quandry quarterly, if not daily.
Contrast this to knowledge. Specifically BJ/math/expertise and the corresponding access to this knowledge. My guess is that if you're a counter, you became one first through the purchase of a book (cost) that required learning (cost in time) and then put into production (cost and expected return), which = ROI (return on investment).
Now to the original (and not forgotten) question.
I would venture that some of the real benefits to GC (bj21) lies in the "ACCESS" to the people that are willing to provide knowledge/expertise for "free" (cost savings).
Think about this for a second. Successful counters place large amounts of money on the line with extremely low advantages, so that every ounce of edge that can be squeezed is taken advantage of. Shouldn't that be your approach as well?
How many companies, as well as individuals, subscribe to trade publications? Now, if all the people at GC, or DD frequently visited and shared their expertise at free sites like this one, then no, there would be no need to pay as you're already getting all the benefits with no cost.
However, if you're serious about extracting every ounce of advantage to increase your edge and positive expectation, then it's a no brainer.
I visit this site (thanks Mayor) as often as the ones I pay for, for that very same reason. You never know where you'll learn something new or extra. It's the price I pay. Now, if cost is a larger issue, and it can be (all new counters are really unsure if this really works despite their protestations to the contrary) then learn all you can for free, but at some point, you'll have to start taking advance courses, and we all know that doesn't come for free.
cheers
bfb