If you are looking for a spare battery
and charger for your w376g, look no further than the lower-end
TracFone Motorola w175. It has the same battery and charger as the
w376g, so you can buy one and use it for spare parts. If you want to
buy it directly from TracFone, I suggest also buying another phone +
airtime bundle in order to qualify for free shipping, then use the
airtime on your w376g. For example, you could get the w175
and a bundle of the Motorola v170 + 120 minute card, all for a
total of $40 plus tax. Then you'll end up with 360 minutes, 7 months
of service, and a spare battery/charger for your w376g.
(ALTERNATIVELY, if you use more minutes, you could also check out the deal on the 450 minute card, which will be doubled to 900, along with the w370, all for $80 by clicking here)
Here's what I recommend if you want the w175 + 360 minutes deal:
1. Go
to TracFone.com's “buy phones” page by clicking HERE. If
you have a w376g, most likely these deals will be offered in your ZIP
code. If not, however, you can also enter ZIP 10101 to find the deals
I recommend. After entering the ZIP, you will look for an image that
looks like this:

Click on “Add to Cart,” then on the next screen click “Go Back.”
Now look for the image that looks like this:

Again, click “Add to Cart,” and then click “Proceed to Checkout.” From here, all you need to do is fill in your order details and complete your order.
Once you receive the shipment, I would suggest first activating the w175 using TracFone.com, and then activate the v170 using the number transferred from the w175 (click here for details on how to do this - it will automatically transfer the minutes and days from the w175). You will now have the v170 with 40 minutes and 120 days of service. Next, call TracFone to have them transfer the airtime over to your w376g (or other phone, if you choose). Finally, add the 120 minute card to your w376g, using code 55532 to get 80 bonus minutes. Your 120 minutes will be doubled to 240, then add the 80 bonus minutes and the 40 minutes transferred from the other phone, and you will have a total of 360 minutes. And don't forget where this all started – you also now have your spare battery and spare charger for your w376g.