Seems if you can still find one on ebay, it may already be modded to take a SIM card, like this: https://www.ebay.com/itm/174709456691
But I guess the specs are too low now for still being usable, the Photon Q is 8 years old now and has only 1 GB of RAM. In 2016, when I had been overusing my second HTC Desire Z aka HTC Vision for so long that it wasn't usable anymore, I thought about getting such a modded Photon Q instead, but I decided that it wouldn't have been enough of a progress over the HTC for me to bother even then. Also, its 4G frequencies didn't include the band used here in Ger