Can anyone suggest a decent inexpensive spectrum analyzer, that I can look
for used on ebay, that would be suitable for evaluating SSB transmitter
output for spurs, harmonics, etc.?

I have a cheap RM Italy former CB amplifier that has been heavily modified
to work on 80 through 10, and has a set of low-pass output filters in a
box with a band switch, all of which I am using with my FT-817. Its
provenance is suspect, at best, and I'd like to be able to check it from
time to time to make sure its output stays clean.

Also I have an old TS-120S that seems to have some serious transmit
problems, part of which is probably spurs and harmonics and
self-oscillation in the finals and God knows what else.

I don't mind paying a fair price for a good spectrum analyzer but I don't
want to pay big bucks for a high-end unit with features I'll never use.

Thanks...