I check prices on ptc ads they do not leave much profit from that area. Most sites had 300-500% markup on them 15 years ago when I started over years as kids got more into it most sites lowered markup. In past few years most sites have ptc ads with none to almost no markup. This is why so many sites with just ptc side fail and only ones with gpt side seem doing well.
Doubt many know as much as I do about industry.