I get the Fermipan at a local grocery store... the price has shot up lately. When I sent it to family 2 years ago, it was $2.50 for a 15.9 oz bag, now it ranges from $4.50 - 5.00, can't complain. It's still cheaper than the packages, and it works. I mix it right in with flour in the bowl (I don't proof it first), add the liquids, and add the rest of the flour as required by the recipe. About 2 1/4 t per pack called for in the recipe, with most of my recipes that comes out to 2 1/4 teaspoons yeast per 6 cups of flour. But you have to watch it while it's rising, it will try to escape pretty quickly!
I was leary of buying that kind of quantity at first, too. But at the time the bags were cheap and the small jars were around $7 so I figured that even if I had to toss some of it, I would still be ahead. This was back probably around '95, before the other yeast changed so I had no idea about that until I kept hearing mom complain that nothing was rising right any more and that she 'must have lost her touch'. She didn't want me to send her yeast because she said she would never use it all. Sent some anyhow, she is back to baking, and she lets me know when she is down to 1" in the bottom of her jar so that I can send more.
I wrote to some of the major manufacturers to ask what was up, Red Star didn't reply, Fleischmanns wrote back and sent literature to tell me everything that we might be doing wrong. I would really love to know what is up!