2007 Revai with no battery - can we add battery?

I am planning to buy an 2007 Revai car which does not have battery. Is it feasible to buy it and install new battery? I am a newbie and not sure what options I have.
Can someone throw some light whether
a) Do we have any battery in market which we can buy and fix it without modifications?
if so, what would be the cost(roughly)?
b) Which is better? Lead vs Lithium ion?
c) Or do we need to specifically make one as this brand is discontinued? If so, where can we get this done? How much would it cost?
P.S. I am currently staying in Hyderabad,TS