While we rarely review earphones and headphones that cost less than $100 - and never review non-Apple earphones or headphones less than $50 - our new Gear section now gives readers a chance to see some of these inexpensive options. JBL's Yurbuds brand has introduced a series of new wired sport in-earphones, Inspire 100 ($20), Inspire 200 ($30), and Inspire 300 ($40). There's also an Inspire 400 set, which we didn't receive. All...