just FYI, none of the carriers really do contracts anymore

(they do "equipment installment plans". this means, once you pay off the phone, you are free to leave whenever you want to and join another carrier. you can even keep the same phone if it's supported on the next carrier)

some iPhone sub-models work on all the carriers, some don't (every year, they keep switching this. I believe the Verizon model is the one you want - works on verizon and tmobile and att, comes unlocked)

not sure if this has any bearing on your work plan+device reimbursement. )