just went to an AP/DE meeting at our HS. lots of parents asking questions! at our school, there is a fee to take a DE class ($250/class); and 3 nearby colleges sponsor them; 1 being the local community college. All classes are taken at HS by qualified teachers. Students can chose to take them DE and/or AP. DE= guaranteed credit; AP, not guaranteed.
Some classes, like AP world history are considered 2 classes, so that’s a $500 fee for the year. If a kid doesnt take the DE credit, the kid then takes the AP test which is $95. There are some scholarships for free/reduced lunch kids. There’s also a small fee to transfer credits from the colleges to the 4-yr U where kids end up. So OP, we are very similar to you, families have spent $3-6K. But they are getting lots of credit for cheap; not sure why there’s complaining!