How much would it cost for service and to replace the sensor on one of my tires for the 2007 es350? Also do new tires come with new sensors?

It depends where you go to have it done. If your replacing your tires they shouldn’t charge you much since your tires are off. It’s basically a stud with a nut to hold it in place. You might have to have it programmed I forget what type of sensors the ES uses.

If one tire pressure monitor sensor (TPMS) has gone bad and your car is at least 7 years old then it is likely more of them will soon go bad due to dying batteries. They have to be replaced with new ones as the battery is integral with the unit. They are not included with new tires.
The price varies a lot. I had it done at Costco for about $225 and a local independent shop quoted almost $500. If you do buy tires at the same time you will only pay for the sensors themselves as the labor to install and balance the new tires will be included in the tire installation labor price. If you only need sensors, as I did, the price was $225 or so.
Make sure they program them to your TPMS system. That should be included in the price. Some places try to charge extra. It only takes them 5 minutes to reprogram your car to the new sensors.
I think it is worth joining Costco, BJs or Sam's Club just to get the great price on the replacement TPMS sensors and they also have great tire prices.

Just had one replaced at Discount Tire (America's Tire in California) - - sensor, tax, installation and programming was $50+ out the door . .. I had 4 on the Corvette done last Christmas - -was about $160 total when buying a $1000 set of tires.

I agree! Costco or Sam's cannot be beat on GOOD tires like Michelin, etc. Sounds like the other fellow got a great deal on his TPMS Sensors, too! I also had one sensor go bad, and since they are 13 years old, you really should change them all. Past 7-10 years, the batteries are ready to die any minute. Gee, I loved the blue color on my 2007 Lexus. Too bad some idiot T boned me about 2 months ago....

I don't mean to hijack the thread, does the full size spare have a sensor already on it?

Yes there are 5 sensors in the car.