My first C3 I bought maybe 11 months ago, $92 incl tax for the kit with nicad and charger, plus I found the inflator on a crazy sale price of $19.99 and its what I use the most. First time I think I topped up 7 or 9 tires before it needed a recharge, but I use it too infrequently I think an a month or so ago I was only able to top up 3 tires (to be fair I have 3 extra cars that have OLD tires and get rarely driven, so top up was 18 to 20 psi to 35 psi.), but Sears replaced it after some fuss with a new one, and back to good charges so far.
LiIon is easily twice as good, and no weird memory issues. Cheapest way I've seen to upgrade which requires both the battery and the newer charger is the $49 drill kit that was on black Friday. I will update, but waiting on a deal and issues with the battery again.