HI,
We also useually buy new phone when its battery gone. We really don't like to shop for batteries and batteries cost much more than phone. U can try to buy battery charger. However, battrey chargers are limited to brands. Some brands have battery chargers other brands doesn't have any.
This one is vtech cordless phone charger:
V-Tech VTi5803 Cordless Phone Battery Charger
This one give u different products spare parts such as batteries and chargers.
Cordless Phone Batteries, Cordless Phone Battery Chargers and Accessories – BatteryValues.com
I am really don'y put my hand in any electronics and my husbend genarally takes care of that. I think boys like to buy and repair all the electronics so I always left this things to him. So I don't know how much I helped u.
Regards
srilak.