I'm a Frontsight member, and have taken eight days worth of classes with them, and can confirm that:
1. Their instruction on the fundamentals are still top notch, but
2. According to the long-time members (and instructors) I've met, the advanced courses have been dumbed down to attract more members (that is, dollars). I have no firsthand experience with this, but I trust the people I've heard it from.
3. People who buy memberships typically get a stack of transferrable coupons (which is what you saw for sale). They are often sold either for profit, or to offset the price of their own membership.
4. Their entire business model is a pyramid scheme, but not a scam (in that those $20 memberships are always redeemed with full rights). They sell lifetime memberships with the expectation that people will show up twice then forget about it.
5. Those people then transfer coupons to friends, who get bombarded with the same 'LAST CHANCE to get Super-duper Primo Membership for just $5,000!' sales pitches. They are easily ignored, but sometimes they do get some interesting deals (for example, 'free' private lessons).
6. They pay their instructors crap, and treat them accordingly. Consequently, most of their best instructors have all either left, or are in the process of leaving. That's not a big deal for the basic courses, but I've heard (no firsthand experience) that the advanced courses have been dumbed down as a result.
I personally bought a lifetime membership from a family member for $200, then chipped in another $1,500 for 'Presidential' membership with another three people that allows us private lessons. For that $1,500, I got six days of private instruction plus a week in Vegas, so I've already got my money's worth; while I definitely plan on returning, I could go the rest of my life without taking another class and still come out ahead. Retail-priced memberships, though, are definitely not worth it, especially when you can buy discounted memberships so easily.