Buy brand new sealed non active

Hello everyone, Ryan Lewis here just introducing myself. Im opening a new all-around wireless solutions, sales and phone repair store in my small town of Webb City, MO. My hope is to open the doors before Thanksgiving. I know I'm doing cracked screen replacement and selling wireless devices (preferably VZW) but I'm pending approval through my current master agent to become a Verizon Authorized Retailer. Odd's are stacked against me so I've been exploring other options and I'm torn on which carrier/carrier's to sell. I'm considering selling T-mobile or maybe being a multi-carrier store. Cable/satellite TV, internet, security systems and iot's I'm interested in selling as well. I'll be selling both residential and b2b. This is my 1st store and I have 5+ years in the industry but I could sure use some insight on the pros and cons of the above mentioned options to sell out of my store. Thank you! Ryan Lewis Owner/President CELLTRONIX LLC.