Massachusetts has launched a new era of shopping. It began last week. Did you notice? Right this minute, if you have private health insurance, you can go to your health insurer's website and find the price of everything from an office visit to an MRI to a Cesarean section. For the first time, health care prices are public. It's a seismic event. Ten years ago, I filed Freedom of Information Act requests to get cost information — nothing. Occasionally over the years, I'd receive manila envelopes with no return address, or secure .zip files with pricing spreadsheets from one hospital or another.