When we first got the bread machine I read the instructions and they said to use Bread Machine Yeast. I went to Wal-Mart and after some looking found the yeast. I had several different choices of yeast to choose from, most of them in foil envelopes. Being an optimist I figured I’d be making lots of bread, so I went for the 4 ounce jar of Fleischmann’s® Bread Machine Yeast. It was more cost efficient than the envelopes and with a screw on top there would be no partial envelopes to deal with.
It worked very well. I’d measure out what I needed for a batch of bread and put the jar back in the refrigerator. After 25 or 30 loaves it was almost gone, so I bought another jar. I was just as pleased with the second jar, but I was making a lot more bread and it didn’t last as long as the first one. I needed a bigger jar than 4 ounces.
After some research I realized that Bread Machine Yeast is another name for Instant Dry Yeast. I went to the internet to see what I could find. The answer was Fleischmann’s Instant Dry Yeast 
The yeast comes in a vacuum package that is brick-like. The left photo shows my yeast before I opened it. From the feel of the package it could have been a solid chunk of wood inside. The photo on the right shows it after a made a tiny cut at the top and let air into the package. It went all soft and it was obvious that it contained something more like fine sand than a solid block. I didn’t open it right away since I didn’t want to open it until the second jar of yeast was empty, so I could refill it. They recommend refrigerating yeast in glass after you open the original package.
Instant yeast has more live yeast cells per gram than active dry yeast, so you don’t need as much. When substituting instant dry yeast for active dry yeast you only need between 2/3 and a bit more than 3/4 as much.
Cutting the top of the package I formed a pouring spout and poured yeast to fill both of the empty 4 ounce jars. My spout wasn’t perfect, and I spilled some, which shows nicely on the black granite counter in the left photo. The two jars held a bit more than half the bag of yeast, which I folded closed and put into a recycled glass peanut butter jar. I left the yeast in the bag rather than pouring it into the peanut butter jar so that no light would affect it while it was in the refrigerator waiting to go into one of the re-emptied yeast jars.
The right photo shows the jars closed up and ready to go into the refrigerator for storage since the vacuum seal on the original package had been broken.
With a pound of yeast in the fridge ready to go I shouldn’t have to buy any more yeast until I’ve made another couple hundred pounds of bread.
After I had written the above I was in the local Sam’s Club and happened to see Fleischmann’s Instant Dry Yeast. They had two of the 1 pound packages shrink wrapped together for under $5. That’s where I’ll be getting yeast the next time I need some.