3 x AA Battery Holder with 2.1mm Plug : ID 3842 : $2.95 : Adafruit Industries, Unique & fun DIY electronics and kits
6 x AA Cell Battery Holder to 2.1mm DC Plug - Ten Pack — PMD Way
Amazon.com: Energizer Rechargeable - Battery Kit - 6 AA and 4 AAA - Batteries with Charger - Energizer Rechargeable Batteries with Powerful Charger just in an Hour 100% 4port - 4port AAA Charger : Electronics
6 x AA Cell Battery Holder to 2.1mm DC Plug - Ten Pack — PMD Way
EBL 6 Pack C Size 1.2V 5000mAh Ni-MH Rechargeable Batteries C +Battery Charger for 1-4pcs AA/AAA/SC/C/D and 1-2pcs 9V Ni-MH Ni-CD Rechargeable Batteries - Newegg.com
Energizer Recharge Plus Combo with Case, 6 AA and 4 AAA NiMH Batteries | Costco
Learn how to build a solar-powered 6 AA NiMH battery charger –
The Best Rechargeable Battery Charger (for AA and AAA Batteries) | Reviews by Wirecutter