I'm not going to say that the Pickering Markets is a fantastic place to shop but it's got a few gems that make it worth going once a month or so.
First off, for those of you who lived in the Amberlea area and miss Stars Pizza, you can find them here on weekends. MAN how I missed that wonderful pizza. The owners run it both Saturday and Sunday and the pizza is always fresh, hot and as wonderful as I remember it to be.
There are a few cell phone booths that sell good cases and quite frankly, you can get some good deals on fancy looking cases or jelly-style covers. There is one place that faces the food area (Cell City I think?) that will normally give you a discount if you buy a few things. Every time we go, we get at least one case and two screen protectors and he always cuts a few bucks off the price (usually $5). Don't let them put your screen protector on for you though unless its the main guy - the usually screw it up.
We were also able to get a VCR here for a good price, brand new in the box. Best Buy and FS were charging an arm and a leg for this outdated technology and we got ours for about $20 to watch old Christmas videos on.
If you're going to come shopping here without a specific purpose, expect to walk around for a while and have lunch. There are tons of little shops selling just about everything yo could ever want and there ARE some deals to be had if you know your prices.
The trade area on the one side usually has some good outlet sales here and there too. I got some good beauty products from a makeup company that was there about 6 months ago and if I'd had more money, I would have stocked up. They also had a pretty good home show (or was it a cottage show) in there with some good deals on sheets as well.