LoHiDirect via Amazon offers the LoHi Tempered Glass Screen Protector for iPhone 6 for $6.66. Coupon code "QIC23P92" cuts it to $1.99. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to bag free shipping; otherwise, shipping adds $6.03.) That's the lowest total price we could find by $10. It resists scratches, fingerprints, dust, and normal wear.

Of note, LoHiDirect via Amazon also offers the LoHi Tempered Glass Screen Protector for iPhone 6 Plus for $1.99 via coupon code "4FIBSW6P" with free shipping for Prime members. (Shipping is $6.01 for non-members.) That's also the lowest total price we could find by $10.