Was the dealership including relearning of the new sensors in their price? If they were, it's not so bad a deal. $65-70 a piece is expensive, but that is the going rate at many shops.
With very few exceptions (the rare non-Chysler dealer that has a DRB III tool, and Crossfire multiplexer and software) it is going to cost a lot to install/activate new TPMS sensors.
Some dealerships and national tire chains (for example, Firestone) will not let you provide your self-procured sensors for them to install while thay are mounting your tires.
Many Chrysler service centers are currently charging an HOUR
labor to perform the very brief relearn procedure using the DRB III. So even if you get 4 of the 20028 sensors for $120, you may end up paying another $120 or so just for the relearn. And you may have to have them installed by an independent shop and then still end up at the delaership for the relearn.
Good luck!
What I did last year because I felt compelled for some reason to have a working TPMS system was to have new tires and my new sensors installed at an independent shop. Despite having the proper equipment they managed to put a few scratches in the rear wheels (ended up offering me half off on the price, which I accepted). Then I started calling Chrysler dealers. Most were 1 hour labor for the relearn. One suggested 1/2 hour at first and then 1 hour when I called later. They agreed to 1/2 hour labor, but then charged me based on $140/hr rate (which must be rate they charge people who don't buy cars from them) and added all sorts of laughable fees (supplies, documentation, electronic storage, etc.). So it ended up I still paid around $90 for the relearn. When I arrived at the dealership I had to wait a little longer than expected becasue they had to borrow the multiplexer cable and Crossfire software from another delaer about 10 miles away.