best TO stores for copper cookware?
Copper cookware must be lined due to chemical reaction.
The exceptions are pots for melting sugar or bowls for beating eggs - yolks and/or whites.
Nickel or stainless is generally available, tin lined is old fashioned since it wears off and must be retinned.
I have seen it at the Cheese Boutique and fancy kitchen stores for insane prices.
Look for (google) the "Mauviel" brand.
If you are serious, and want to buy 4-6 pieces, you should go to France. The money you save will pay for the trip.
And I'm really not joking!!
There are a few places in France shipping to North America. Savings are considerable, and you can get well made brands such as Mauviel.
eBay is another source. Some new but unused items turn up frequently.
A few manufacturers, such as Caphalon, have a line of sandwiched copper pans: outside layer is copper, followed by aluminum and finished with stainless steel, I have a couple, and they do not have the same quick performance as copper/SS, but are more like aluminum/SS.
You can get Baumalu a lot cheaper. Make sure you get the 2mm cooking pans rather then the 1mm serving pieces.
SS lined is the best (IMO). Mine are all tin lined and I suspect it will be many, many years before I need them re-tinned. You can get a few Baumalu pieces at some Home Sense stores. I picked up a 10.5 inch frying pan for < $50.