ok so im starting to get into the sound systems right, still a noob, and i got my first car about a month ago (99 mercury cougar)

ive been seriously searching for some subs now and am getting offers from all sides, here is the one ive been considering the most:

2 12 inch Alpine R subs (used)
Double sub box with custom green tint (matches my car)
MTX 600 Watt amp
Full wiring and capacitor and installation
No warranty

he says its valued at 1550$
hes offering me 650$


The guy is a friend of a friend and works at best buy in thhe audio department.... what should i do???