Buying a cell phone will be cheaper than renting (and then you have it available for other travel).
Fees for texting are generally not terrible, just disable any data plan.
I have an unlocked phone and when I go to Europe I use a SIM card I bought from Orange in England. Their pay as you go never expires (which is unheard of) and great if you travel to Europe more than once in a blue moon. Their roaming charges are very reasonable, too.