with low budget u only can get cap ayam stuff...save up your money some more la, dont rush...

just start with the cd player first. 400-500 can get u kenwood, sony, jvc, clarion, 500-600 can get u pioneer or alpine.

next stage save up for component speakers, 700-800 will get u entry level models of some good brands

after that only save up for an amp, starting around 800 maybe, plus 100-200 for wiring

for tips on brands, go to the thread discussing good brands for car audio