every Spypoint camera (Cellular Trail cameras) comes with a preloaded SIM card in it. The camera communicates with the app & the server through that SIM card by using the modem.
Your cellular provider doesn’t have anything to do with the provider that is used for your Spypoint camera. The important thing is to check if that there is a signal strong enough from any provider to allow your camera to connect to that network. This is essential, as Spypoint cameras do not have the “roaming” feature that most cellphones have, and are unable to connect to all networks. It’s better & recommend checking the coverage maps for Verizon and AT&T to verify that the signal will be sufficient for consistent and reliable service. Cellphone networks such as Straight Talk Wireless are usually not independent cellular providers and run off of the other major networks in the area, using AT&T, Verizon, Sprint, or T-Mobile depending on the specific model of the mobile phone purchased.