I think the point of the above posts is this:

Research how easy it is to get 22lr ammo from where you're at. If you can get it cheap, then a 10/22 is worth it. If ammo is hard to get, then a 10/22 won't be worth it, cuz you won't be able to shoot it!

The fun of shooting a .22 is that you can blast away at targets and not blast away at your wallet. However, if 5.56/.223 and .22lr cost the same, I would be shooting my AR a lot more.