First of all, it's a great opportunity(those already in the group can attest to this) - but mainly just for a certain small subset of people. Certainly it's a solid alternative to paid coaching, in which hourly sessions are typically very expensive ($50-100+ per hour) and often difficult to get much value from a limited number of one-on-one sessions in rapid succession since students generally miss out on further iterations of the study -> practice -> review cycle...among other things. There are plenty of poker players who find themselves in that gray area of wanting to improve their game, but don't want to (or can't) spend even more money from their poker roll.
Groups are far more efficient, allow for people of similar skill to learn together, and are much easier for those with busy and/or fast-changing schedules since you can always catch up on the content on a later time at your leisure and at your pace. Personally, being in my first group back in the pre-BF days is what took my game to the next level and I strongly recommend it to anyone who is seriously looking to improve.
Some experience playing o8 is certainly preferred, but I've seen plenty of holdem and omaha regulars make the transition and use it in addition to their previous games to further boost their earnings. A strong work ethic is important, some time to dedicate to learning/playing, and most of all you simply have to enjoy poker or it will eventually become too much of a grind.
In addition, those who are in low cost-of-living areas are at a distinct advantage for numerous reasons - mainly in that the smaller, softer stakes are more meaningful. Or those who are currently losing at poker and possibly becoming frustrated with it.
Why free? Because I can
And because I'd like to see the game grow even more than it has already. Other freebies are available too 
Post and DM me here if interested, to discuss it further. Graphs and such are available upon request, multiple platinum stars on sharkscope for o8 SNGs. Also others are around to help with certain specific aspects/specialties, or even other formats like omaha or holdem.