Not at $10 per tire, and many unscrupulous dealers charge more.
This website promotes their machines (as cheap as $500) by saying and providing tables that show that this can soon become the most profitable service in the shop.
http://www.nitrogentiremachine.com/While the nitrogen fill has definite benefits for aircraft and racing tires , and fleet-owners who can't enforce regular tire checking, it is not the panacea that Jay Leno and others suggest. Checking tires regularly and filling with good old compressed 80/20 will do almost the same thing.
Anyone remember telling bystanders they had "racing air" in their performance car tires?