Cheap low power design for computer speakers

[haut]

I'm looking to build a low power amp (under 5w is fine) for use with some nice DIY computer speakers that will be only about 2 feet from me. I want it to be small (4"x6"x8" case is ideal) and inexpensive. How complicated of a circuit do I need? I want a selector for 2 inputs, a volume knob, and a power switch on the front, nothing else needed. I might use 4 ohm speakers with it, so I'd like it to be able to handle low-ish impedances. Is this doable for under $40? What type of amp should I do? Are there any designs available for free that would work well for this? I searched for some topics but couldn't find anything that answered these questions. Thanks!
--Ryan

[subwo1]

For low power, my first choice is usually an IC based amp using something like an LM3875. See National Semiconductor's Web-site for possible IC chips and schematics.

[haut]

In doing more searching I found this: http://sound.westhost.com/projects-1.htm
which seems perfect for what I want, but still I wonder if its possible to build an amp from scratch (the case and transformer seem really expensive) for under $40. I've seen lots of really nice looking cases in people's projects, are these custom? I like the brushed aluminum/SS look and would love to build something like that but it seems like the case alone could be well over $100. As far as building amps that compete with the standard "good" amps (I like the sound of our Outlaw 1050 receiver), how much is saved cost wise? I've been building speakers for years but haven't got into electronics because of intimidation. Now I'm learning more about amplifier circuits and it sounds like it might be fun. Thanks.
--Ryan