Zarak,
Subs are probably the easiest type of speakers to build, there are a LOT of good kits out there and a lot of good information available.
It's all about getting the best bang for your buck, you don't include your time because it's a labour of love. You can make it look like a plant stand or an end table, or just a big old box. You can veneer it, laminate it, paint it or what ever you need to do to have it blend into it's surroundings.
Going to the expense of buying a lot of tools is no longer required, there is a company in British Columbia making mitred corner mdf boxes than can be assembled by an apartment dweller.
http://www.creativesound.ca/
Bottom line I think is it's all about the satisfaction of building it yourself.
