Whoa. As I type, Amazon's prices for the paperback of Farmer in the Sky is "from $24.57". For that, I'd demand it be read to me in person by Gal Gadot.
Kindle version is just $6.99, though. That's OK. You can also get it as part of a four-novel hardcover anthology "from $6.43", but I assume that's a SF Book Club edition that might be falling apart.
My version cost me a cool 50¢, published 50 years ago. Couldn't find a pic at Amazon, though.
Anyway, one more book down in my "Rereading Heinlein" project. (And thirty-three to go.) It's a surprisingly dark juvenile, originally published in 1950. You can think of it as Little House on a Jovian Moon. The narrator is Bill Lermer, a teenage Californian; he and his father, a widower, decide to apply to be the first massive wave of immigrants to a terraforming-in-process Ganymede.
And it's a darn fine yarn. Bill and his dad have all sorts of crises, adventures, and setbacks. Heinlein skillfully builds his count-the-rivets world using a minimal amount of handwaving magic technology. I think you could—and Heinlein probably did—sketch out a floorplan of the Mayflower, the ship that transports the colonists from Earth orbit to Ganymede orbit. ("And right down here is the magic engine in which mass is converted efficiently to kinetic energy.")
Along the way, Bill grows from a semi-petulant kid into a mature human being. Heinlein does this with show-don't-tell prose. Bill is—literally—a Boy Scout, and gets to implement most, if not all, of the twelve tenets of Boy Scout Law. (Heinlein, of course, would be weak on the "reverent".)
I haven't read the book for fifty years, but it holds up pretty well. For all the advanced space tech, everybody still uses slide rules and wire recorders. There's a final adventure that is kind of a machina ex deum, but I didn't care.