LG is holding an interesting limited time deal for accessories in the US, as it turns out. You can save 60% when you buy a replacement battery, 50% when getting a charging cradle, and a whopping 70% when combining the two into a bundle. The smartphone models for which you can purchase these accessories at such steep discounts are the G4, G3, and V10. Do note however that only the battery is available for the G3. No matter which one you pick, each battery or charging cradle now costs only $15. But when you pair a cradle with a battery for the same device, you'll only pay $20 total....
Source: http://www.gsmarena.com/lg_is_now_selling_batteries_and_charging_cradles_for_the_g4_g3_and_v10_for_15_each_10_when_bundled-news-17764.php