hello all! the handyman in me is compelled to try to build my 1st HT DIY project and i would love some advice....i have decided to possibly try a subwoofer, as it is the only part of my setup that i am a little underwhelmed with (It's a tiny Sony SAWM20 (?)my questions/comments are these: 1. needs to be VERY inexpensive (not much $ plus it is kind of an experiment, so I don't want to put a lot of $ into it yet - under 100$ hopefully, not including wood/MDF etc.) 2. please keep in mind I know NOTHING about electronics, so pre-built crossovers and such are a must for now 3. how could i power it cheaply? is there any way at all to build a self contained unit (i.e. a sub that wouldnt have to have a separate "outboard" amp) 4. not necessary at this time to be an "awesome" sub with precise airflow calculations or whatever...just something decent & better than my miniscule Sony 5. can't be huge all the DIY speaker websites I've been to are still a bit too complicated for my inaugural project...i need something well planned/laid out... any help/ideas?