system for my car?

so im plannning on buying some subs and an amp and all that good shit for my car
but im gona buy them used from either a friend or like off craigslist or something and i was wondering which boxes are better to have the bandpass ones that are like clear in the front or just a normal box
i dont really know much about subs i just know i want a banging ass system
so somebody out there please help me with as much knowledge and know how of sound systems
let me know what youve got what i should get anything would help
im on a budget thats why im gona buy them used i only have a couple hundred to spend on it
any advice is appreciated:rasta:

to be honest a couple hundred wont do crap for a sound system unless you install it but the wires cost about 70, i personally have a good system two 12" alpine subs 900 watts max power and i have a nice stereo with 50 watt max and i also replaced the stock speakers with polk audio ones just replacing the stock speakers cost me 200$'s which i would recommend doing first and the best place to buy all that stuff is on ebay it is sooo much cheaper but remember you dont get a warrenty so if it breaks your screwed but my whole system costed me about 600-700$'s that is what you would be lookin at if you wanted a system that shook the other cars beside you haha and it also depends on how many speakers you have in your car mine only had 4 because its a 2 door but just some decent subs that will last are like 70 a piece on ebay but if you buy it from a stor you would be looking at 120 + i hope this helped you out

yeah ive already got the speakers taken care of
what type of subs would you suggest