This is the source for the "is anet" series of websites: isanetbelow60, isanetabove200, isanetabove300, isanetabove400
I use it to check the Arista stock price.

Two files are created:
bin/STOCK_RT.json to store the real-time price and timestamp
bin/STOCK_HIST.json to store historical prices, used to generate trend/histogram

A crontab runs the isanetbelow60.py file periodically:

/usr/bin/python ~/isanetbelow60.com/bin/isanetbelow60.py