Catalytic Converter Beginner

Hello all, long time lurker, and just decided to finally make an account after searching the web for everything cat related, and ending up with quite a lot of new information, but not enough to start buying locally quite yet. I've been parting out totaled cars by myself for about 2 years now and selling parts, selling the cats, and recycling the chassis's to a local recycler. Obviously every one of of the cars we get has cats on them, at first we were getting ripped off and a guy used to come by and just give us a $100 dollars a cat, no matter the cat. After some research, we found out we were being made fools out of and found a guy that started paying us based on the part number. Any how after some research I started to want to buy and sell cats locally, after days of researching, and finding many helpful threads that APA answered too I learned a lot. But at the end of the day I still dont understand a lot, for example, how do you price cats based on the part number, I haven't found anything but rough estimates online for example by RRCats that gives $60-107 for small foreign's, $148-263 for large foreign's etc. How do you price cats by part number? Prices on metals are always fluctuating, so how do you update prices daily? Do most of you guys just resell, or send to refineries? I see a pretty good opportunity because in my city I personally know many people, shops, mechanic shops, and even small junkyards that are still being ripped off, and they have a pretty decent amounts of cats that they collect monthly. I know that's a lot of info that i'm asking for, and if thats too much info to give out I totally understand. If anyone can point me in the right direction, give any tips on where to start researching, or what website or article to read, that I haven't already, would be greatly appreciated, thanks to APA once again for all the helpful information you've already given out on this forum. This forum is a a great help. Have a good night guys .