Making bread in a bread maker using regular yeast not bread maker yeast
A packet of instant yeast is approximately 2 and 1/4 teaspoon of yeast. 

Please note that instant yeast used in bread maker is slightly different from active dry yeast. Instant yeast will generally be much smaller granules and can be mixed directly with the dry ingredients without proofing. Active dry yeast will be larger granules and often times require proofing. However there are several brands that does not require this extra proofing step.

Note that not all instant yeast come in small packets. I have used SAF Instant Yeast with very good results.