Every Christmas I sew as many pairs of these quick and easy pj pants as we have family members (our numbers are ever expanding :). You can sew up a pair in less than an hour, and if you assembly-line sew, you can make several pairs in an afternoon.
Simplicity Pattern 2290 (or other one pattern piece pants pattern)
Material yardage as suggested by pattern
Elastic as suggested by pattern
Cut two pieces of fabric from one pattern piece
To serge inside leg seam, fold each leg piece right sides together and pin.
Serge long straight seam on inner edge
To serge crotch seam
Turn one leg inside out
Slide this leg piece inside the other, right sides together
Once the leg is inside, slide around until the pieces perfectly match so that the crotch seam is exposed
Serge crotch seam
Divide elastic into quarter sections and mark each quarter section with a pen. Do the same with the waist of the pants.
Serge elastic ends right sides together creating a circle of elastic.
Serge elastic directly to waist, right sides together stretching elastic to meet quarter marks as you go. Turn down and stitch with conventional machine, stretch stitch.
Hem pants using the narrow hemming foot on your conventional machine,
or serge around the bottom edge of pants leg, turn under 1/4″ and straight stitch with conventional machine.