This is a problem when you can be almost sure, not to have more than 2 inserts per box. Those auctions are the result ...
But everybody should know that ...
Well I know I was very lucky, but I did get 5 inserts in one box! (It evened out over the case pretty much) but still - there is always hope. But to be honest, at $1 each the seller couldn't afford for these to be packs with a chance of an insert in - even at the best price I have heard it costs more than $2 a pack.
The age old saying "if something looks too good to be true, then it probably is too good to be true" still stands!