Next time you’re at your local club, ask around to see which member is selling ammo by the case.
I spent a few years on the road building, and always shot at the local clubs. At every club, there was always a member who was a dealer, and stock ammo to sell that was less than $30 a case (250). Granted that it will not be AA's, but unless your stock piling hulls, it doesn't really matter.
Also, the other thing to keep in minds is that the AA and other competition shells will have a lot less felt recoil than the plan Jane ammo that you get for a discounted price. So if you plan on reloading, or shooting shells by the case, your best bet would be to just start off buying the AA ammo, but buy it buy the case to save some money over the single box price.
I should note that on the skeet range, even the cheapest shells will crush the target due to the short range. You’re just going to feel a bit more recoil.
Where the cheap rounds fall on their face is the longer ranges like the 27 Yard handicap in trap, or a long passer in sporting clays. The shot is out of round, and is not hard shot. So once the distance greatens, the pattern will begin to have holes in it, due to the erratic flight pattern of the obliged shot, and possible pattern blow out from the muzzle/wad blast.
Hope this helps.