A laptop does not need a battery charger... when you plug them in, they draw enough power to both run the machine and charge the battery.  The exception might be when you have multiple batteries for your system.  They may sell chargers for that at the manufacturer's site.

As far as Dell Auctions is concerned, I've never heard of it.  I have, however, used Dell's website to buy refurbished items (both laptops and desktops).  I've been very happy with the results, and saved a pile of money.  Try that.