A lot of people who jobs where co-workers take over their responsibilities while they are gone have trouble understanding what self-employed people have to do to able to walk Camino. As a self-employed person who has no employees, I had three choices in life: (1) never walk the Camino and keep my company intact, (2) walk the Camino disconnected and literally destroy my company and this my livelihood, or (3) walk the Camino and continue to run my business remotely in the evenings. I chose the third option. And in order to shield others from the audio and visual noise of me conducting business five nights a week I stayed in albergues with private rooms and cheap hotels (along with four Paradors).
I used the Verizon plan. I believe it's $5 per month and cuts international calls down to a $1 a minute. I also took advantage of the ubiquitous wifi along the Camino to respond to emails. Because I needed over 300 people to have my phone number, I didn't put a Spainish SIM card into my unlocked phone (unintended consequences of putting g a "cheap" Spanish SIM card into your phone is having to let everyone what your new number is and then they have to pay an outrageous international fee to call you).