Few high schools, and even fewer middle and elementary schools, are teaching the coding courses families want.

No coding classes at your kid’s school? More than 90% of parents want their child to take a computer science course, but only 35% of high schools in the United States offer one -- and the middle and lower school numbers are far lower. So how can families expose kids to coding, and do it without breaking the bank on pricey summer camps?

Several free, easy-to-use, beginner computer pro...