If you want a cheap setup, free air is the way to go. Lots of discussion on it and plenty of options for subs and amps combos, you just have to make sure it fits.
My ride(Cardomain link) :
'95 Contour 16V Zetec DOHC, Teal , ATX
Born on Sep. 4, 1995
86+ miles
*LEDs mods are on their way!*