For more information and to purchase online:

Season 1:
http://www.amazon.com/exec/obidos/ASIN/B0000ZMH92/ref=nosim/happydaysonline3-20

Season 2:
http://www.amazon.com/exec/obidos/ASIN/B0002RQ3MU/ref=nosim/happydaysonline3-20

Season 3:
http://www.amazon.com/exec/obidos/ASIN/B0009X7BF0/ref=nosim/happydaysonline3-20

The Complete Series (Sony):
http://www.amazon.com/exec/obidos/ASIN/B0016MJ73W/ref=nosim/happydaysonline3-20

The Complete Series (Mill Creek):
http://www.amazon.com/exec/obidos/ASIN/B00THX0SUI/ref=nosim/happydaysonline3-20