Most, but not all, loudspeakers are happy with an amplifier that has a fairly high damping factor (fairly low output impedance). The exceptions are typically high efficiency speakers, especially single-driver ones, whose otherwise thin bass is warmed up by a high output impedance amplifier such as an SET or OTL amp. And those can be very interesting speakers to play around with.
I don't know of any amplifiers in your price range that have a widely adjustable output impedance, but in my opinion that would be a very desirable feature for a single amplifier that would work well with a wide variety of speakers. Wolcott makes such an amp, but not near your price range.
I mention this in case you stumble across an amplifier that offers adjustable output impedance in your price range, as I think this is a feature that would serve your needs very well.
Duke