Wow. I'm impressed. If our kids take the college credit classes at the high school, they have to pay about $150 a class (for 3 college credit hours.) If they take the college credit on the college campus (while still enrolled in high school), they pay about 30% less than the going in-state college rate (i.e. they pay about $200 a credit hour, or about $600 for a 3 hour college class.)
Some of the private colleges in the area have offered college credit on their campus for $50 a credit hour to homeschooled students.
You've got a sweet deal though; smart to take advantage of it.