The 122.99 must be a mistake. I personally wouldn't shop ebay for batteries.
As far as I am concerned, ThunderPower is the gold standard, and you can get the
newest 70c G8 in the size you need for about 60 bucks direct from Thunderpower.
The 45c G7 is even a better value at about 45 bucks. To some extent,
my experience has been that you get what you pay for, but you might be paying for
something (high c rating) you don't really need.

If you want to go cheaper, I've had good luck with GensAce, from Hobbyparts.
Another brand I've had good luck with is Glacier, from EPBuddy. The 3s 2200 35c from them is about 25.00.

I don't know anything specifically about the KDS charger,
but in general, lipo chargers will charge any lipo battery regardless of the c rating.