I guess you could call around and see who has those Federal at what prices. Sometimes you can buy something uncommon like that for a cheap price because it has been sitting for a long time and it hasn't been reordered which means the price hasn't changed. That's how I got a lot of my 16 gauge loads actually.
Remington makes a 16 gauge Foster type load and you can buy them anywhere. I just took a look on Cabela's website and they are priced at $7.99 presently.
I use the 1 oz Federal Game-Shok in #6 or CIL Paperhull in #6. Are those 1-1/4 oz loads pheasant loads or just heavy game loads?
Those 1 1/4oz are wing shok from Federal, they are probably pheasant loads. The slugs can be found, the buckshot seems to be tough to find now, I think companies started to discontinue it a few years ago.
I picked up a couple boxes of SG imperial for $20 last year