Where can I get information about the 12 volt battery?

I'm having a hard time finding a quote for the price of a new 12 volt battery for my 2002 prius.

I think Optima battery and installation kit for Prius 2001 to 2003 would work, and that's about 200 dollars, can i get one for less? the dealership is charging me over 400 for a new one plus labor plus tax. I'm not doing that.

Help please! I already spend way too much money to get my engine and battery replaced...