I switch between Xfinity and Fios as contracts expire. Try to keep broadband of 50 mbs or higher around 30-40 a month.
I do the exact same thing, and have been for about five years now, although I only do plans with no contracts.
I am currently paying for 60Mbps service with Comcast for $30 a month. It is for 12 months, and at the 11 month, I will switch back to FiOS for their "new customer" rate.
But, it sucks for many people that only have one ISP to choose from, it is not as easy to become a new customer, although, it is not impossible either.