jc,
For your educational purpose only here, I cannot give you any recommendations for really inexpensive amplifiers.
Watts are not the only thing that need to be taken into consideration with amplifiers in general. Amps being delivered is also very important, as it allows for drops in impedance and "head room" for how music is actually delivered.....reserve power if you will. In some cases I would also say that amps are more important than watts, but most manufacturers don't post maximum current delivery.
Amplifiers with high current capability will usually be rated at 8 ohms (say 100 watts), and into 4 ohms (say 200 watts), and sometimes into 2 ohms (say 400 watts)......usually double, or nearly double the previous spec.
Amplifiers that cannot do that, usually are incapable of delivering high current. All watts are not created equally, or "watts are not just watts"; current delivery is also very important.
Also note that higher current delivery, can generally be associated with more expensive gear (though no always). And please know, these are just generalities....there are always exceptions to the rule.