@mozinfotech,
The commoiy market in my neighbourhood opens on Tuesdays and Fridays, so on Mondays and Wednesdays I always make sure that the commoiy section in my freezer is run right down so I can fit more in if they are being sold at a good price.
Tip: Always pull on the dorsal flap of a commoiy to test for freshness. If it snaps back into place when rekeased, it's fresh. If it just hangs there looking all flabby and limpid, avoid buying it unless you are going to cook it that evening.