Luanna, I was researching sources for steel plate in your area and I noticed that you're quite a bit further West than I expected. My knowledge of Canadian geography is not what I thought it was. Is this the Don's Pizza you mention in your profile?https://www.facebook.com/62666407798/photos/a.82552352798.86238.62666407798/82553457798/?type=1
If it is, then perhaps your goal isn't NY style after all, as this could easily be either Midwestern thin crust or possibly even cracker style.
This all being said, steel can still do midwestern pizza just as well as cordierite and will last longer, so even if NY style isn't the direction you're heading, I still think it's a good idea to purchase the material that provides the greatest possible range of styles for your oven- steel.
If Don's pizza is your bliss and you're confident that's the only style of pizza you're ever going to make, then I'd suggest Axner (cordierite, cheaper than California stones for the same material).
Otherwise, if you still want to pursue steel, the first step you want to do is measure your oven- carefully. You want the largest square plate you can possibly fit- touching the back wall (or back lip of the shelf) and almost touching the door. Don't just measure the shelf, as there's usually a gap between the shelf and door- and any extra space is critical.
I'm guessing you can probably squeeze a 16.5 or possibly even a 17" plate on the back wall to door dimension. Side to side, 18" would probably be good. Whatever front to back dimension you get, split it in half to get two pieces. For instance, if your back wall to door dimension is 17, you want to ask for two 8.5" x 18" x .5" plates. Cutting the plate in half makes it a lot easier to take it in and out of the oven.
Once you have the exact dimensions, here's what you want to ask:
"Hi, do you sell a36 steel plate to the public?" If the answer is yes, then
"Is it salvaged and/or heavily rusted?" If no, then
"I'd like a quote on two ___" x 18" x .5" plates"
Here's the list of places to call in your area (taken from a google map searches for 'steel near sault ste marie, ontario' and 'metal near sault ste marie, ontario' ):
Traders Steel Warehouse
215 Drive in Rd, Sault Ste. Marie, ON P6B 5X5, Canada
+1 705-256-7957 · traderssteelwarehouse.ca
Bunker Manufacturing Inc
1501 W 12th St, Sault Ste. Marie, MI
(906) 632-3829 · bunkermfg.com
Sault Machine Works
1435 W Easterday Ave, Sault Ste. Marie, MI
Soo Welding Co
934 E Portage Ave, Sault Ste. Marie, MI
(906) 632-8241 · soowelding.com
Essar Steel Algoma Inc
Queen W, Sault Ste. Marie, ON P6A 5P2, Canada
+1 705-945-4800 · algoma.com
China Steel Inc
164 Industrial Park Crescent, Sault Ste. Marie, ON P6B 5P2, Canada
+1 705-942-3200 · china-steel.com
waterjet cutting · conventional machining · fabrication · cnc machining · robotic
Ro-Von Steel Inc
465 Second Line E, Sault Ste. Marie, ON P6B 4K2, Canada
+1 705-759-2011 · rovonsteelinc.com
920 McNabb, Sault Ste. Marie, ON P6B 6J1, Canada
TESC Contracting Company Ltd
565 Dundas, Sault Ste. Marie, ON P6A 1A6, Canada
Custom Sheet Metal
6505 S Nicolet Rd, Sault Ste. Marie, MI
Maygar & Sons Sheet Metal
744 4Line E, Sault Ste. Marie, ON P6A 6J8, Canada
Bob's Sheet Metal
2 St Michaels Sq, Sault Ste. Marie, ON P6C 2V7, Canada
I haven't check every website, so some of these companies are probably wholesale and some might not even have steel plate. For the places that do carry it, expect to see a pretty big range of quotes, but one should fall in the $35 to $65 realm. Bear in mind, for a lot of these places, the pieces you're looking will most likely be scrap that's left over from another job and that will take them very little time to cut (in other words, no skin off their back). If you're dealing with a corporate structure, that tends to drive the price up, but if it's just one person or a small company you're dealing with, when they quote you a price they're usually not thinking "okay, what's the steel and my time worth?" but, rather, "what can I get out of this person?" Because of this, I probably wouldn't mention pizza and it probably wouldn't be a bad idea to have a male voice asking the questions as I'm sure there's fabricators out there who might charge more for a woman based on the (false and chauvinist) assumption that women might know less about these kinds of things. It's sad, but these people do exist.