They replaced the complete throttle body and fuel filter for this price, or did they just clean it? Don't understand, the repairs to date seem to have nothing to do with the trouble code.
If an A/F sensor, B2 S1 means Bank 2, Sensor 1. But this is not the real trouble code number. These is the first sensor on the rear bank of cylinders nearest firewall.
You can buy your own aftermarket sensor and intall it. Suggest the Denso brand as it seems to work better with Toyota. Try online sites such as
www.rockauto.com and there are others.
Determine if the car is built to California or Federal emissions standards and be sure to get the right sensor. There should be a sticker on the hood with this info or at least the words CALIF, if such.