I bought a used Harmon Kardon 380i stereo receiver about 8 years ago for $40.



You can find its specs in pdf here:
http://www.eserviceinfo.com/downloadsm/46951/Harman/Kardon_HK380i.html

At 30 wpc at 8 ohms, it plays very solid in my home office with both pairs of speakers to which it is attached (Tannoy Revolution 3s and Angstrom Legattos).
My office is about 8' x 15' and i've never had a requirement for more SPL.

There are more used ones out there, dirt cheap.

"Those who preach the myths of audio are ignorant of truth."