My apologies if this has been covered already. The original poster asked for 1-2lb quantities of active yeast. I suggested a source for instant yeast.
Active and Instant yeast are two different products. Active yeast is dried at a high temperature, which kills many of the yeast cells. Therefore, active yeast must be "proofed" in warm (105-110) water to get rid of the dead outer layer of cells. Instant yeast is dried at a gentler temperature, so almost all of the yeast cells are live. No need to proof instant yeast, it can be added with the rest of the dry ingredients in a recipe. You can use a smaller quantity of instant yeast in recipes calling for active yeast, since there is a higher percentage of live yeast cells. Active yeast is stable for years at room temperature. I keep my instant yeast in the freezer to prolong its life. Either product will get the job done, but my personal preference is instant yeast.