[quote name='snuter']I think I saw my local Blockbuster video trying to sell the Intec brand DS Battery replacement for $5. I'm pretty sure I saw it at multiple locations so maybe give that a try next time your at BBV. Keep in mind that it was on clearance, so supplies might be limited.[/QUOTE]
I got one for $2.25 at Blockbuster a few months ago, I think that's your best bet, OP. It even comes with the screwdriver. It said that it gives you an additional 8 hours of gameplay, so I guess it's not as good as the real thing, but it's pretty cheap so yeah.