As one of its daily deals, B&H Photo Video offers the GoPro Official Accessory Bundle for $19.99 with free shipping. That's $29 less than what you'd pay for just the battery charger and battery listed below elsewhere. Deal ends today. It includes:
HERO4 dual battery charger
dual-USB auto charger
2 x tripod mounts
These lucrative gigs let you work in your slippers.