Most often available in local greengrocer, it makes much more sense to grow it yourself.
Parsley seeds strike well, and quickly, (3-5 days), you can grow it at any time of the year and because it is essentially a biennial, you get great value from any one plant.
Apart from the usual supplementary benefits, the Parsley leaves, stems and root are diuretic, and reduce the production of histamine which we find a boon while out mowing the lawn.
The Parsley seeds are wonderfully aromatic as well, making every part of the plant useful.
50 fresh seeds $3.50
Degree of difficulty in germination.....2/10 (1 is easy - 10 very difficult)