I designed this tiny altimeter for my younger cousin, who is getting into Estes rockets. It can log 50 flights onboard in memory, and then export their apogee over serial to a computer.
At its heart, the entire thing runs off an AtTiny 1614, which I am going to run off of Arduino code. Programming will not be fun, since the altimeter on the board does not have a library. I'll have to write my own, which has so far been a slow and painful process.
Once he gets into bigger rockets, I have a Mk. 2 designed that will log the altitude to an SD card at about 50Hz, that way he can plot the rocket's path and see how it flew.
The economics of scale really kill you when the stuff comes from China. To order 1 would cost nearly $60, or if I buy 20 they go down to $5 per.
The blank boards are like $5 whether you get 1 or 100, beyond that the altimeters are $2 per, the voltage regulator I went for was around $0.9, the connector is $0.5, all the way down to the resistors at $0.001 each.