This really connects to socialism. China used to have "Price Bureau" (物价局). It sounds like Sanders is calling for one in the U.S.
Also, if "affordable price" policy is needed for internet, why not needed for more basic stuff like food and medicine?
Maybe food is too expensive for the poor because there is no Price Examination Department (物价检查所) to check price in grocery stores?
Current policy already has mechanisms (broken though they may be) to provide affordable medicine to people, ranging from government provided medicaid to income based discounts on drugs.
Current policy provides subsidized food to everyone in the country (and outside of the country, which is something of a sticking point on trade negotiations). We additionally provide further subsidies on a need based basis through the SNAP program (aka, food stamps).
Prices are already highly regulated for other utilities like electric and water (although, I am not sure what regulationd exist at the federsl level here)
EDIT: also, China is a rapidly growing economy that has overall had very succesfull policies. We should not blindly copy what they do, but "China did it" is not a convincing arguement.
Also subsidiaries are different from price control.
It is and Medicare for All is a popular policy proposal.