Business is business, people gotta get paid to feed their families too. There are tons of resources online for DIY auto repair, you just gotta learn what to search for and then know what you're looking at.
I don't know what year your car is, but a quick google search for "Hyundai Sonata cam sensor" instantly brought up a few results for cam sensors for later model cars that were around $50. Remember, that's from a website that has less overheard than an auto repair shop does. The shop probably bought the sensor for $50 and then has to make a profit on it, so they can further stay in business to serve people just like you. Again, business is business