wat is roughly ur budget for an amp, cheap is bit loose definitive word here in da ICE world....

to some ppl RM150 is cheap while to some others RM1500 is also cheap....hehehehe...

by the way, since ur car is kancil (a small car) u dont really need a 6X9, the front component set shud be good enuff for rear filling (as said by nightzstar)...

if u still insists that u need rear speakers, get 2 way coaxials...cheers...