It really depends on where you are, the brand and the size..
I noticed that all their pans are anondized. I don't like anondized pans.....they cause the crust of my cakes to bake too brown. I like shiny pans....the yeiald a very light colored crust. The last couple years I've purchased 2 inch deep pan pizza pans from a restuarant supply and love how the cakes bake in them.
They are expensive generally but they last a lifetime. Just DON'T buy the Alan Silverwood Multisize cake pan because it is a huge flop and a big waste of money. I bought it last month believing the advertising that it will bake any size, any cake... turns out it is only good for fruit cakes (very thick batter) and only double lined :( Not good with sponge cakes. And you can't double line small sizes, i.e. 5 inches or less. It still leaks and the lining messes up the shape of the cake. Really really bad purchase :(
thanks everyone for helping me
Just buy Magic Line Square Cake Pans if you're going to buy online anyway.
What Apti said.
OP: That site you mentioned no longer has square pans.