I want to be able to take my audio from stock to decent with good subs for as cheap as possible.

Could anyone help me and give references on what to buy/how to install?

Thanks.

 

First, determine your budget.
I spent around $350 to get it going, sounds good to me, and I have had high end systems at home over the years. Just a head unit, dampening and speakers
My car could use a powered sub, but unless I get one for under the passenger seat, I won't bother, I can't seem to justify a $1000 system in a $2500 car.
I also wanted iPhone and Bluetooth some things that you might not need.

 

gotta pay to play my friend. whether it be cash or work. its gonna be expensive. if your willing to do the work to make it sound good might not cost you as much money but if you just want to buy a cheap sub and drop it in a trunk box dont expect all that much.

the cheapest I would go if you just want to drop a box in the trunk and call it a day.
dc 8" sub. (should cost you around 150 dollars)
loc (30 dollars)
precision power 550.1 (140 dollars)
amp kit (50 bux)
that is a nice amp, one of the best all around subs on the market, an amp kit and a signal for that amp for under 400 dollars. build the box yourself to spec. a sheet of 3/4 mdf is cheap. that sub will produce plenty of loud, clean, low bass.