I think that there are lots of IEMs in the $75-150 range that sound really good. It's a bit tricky, since fit and sound preferences come into play.
Are you looking for isolation? Or just portability? Would you consider second-hand IEMs?
I have the following * Fiio F9 (though I'd get the F9 Pro if I were getting them again, they weren't available when I purchased them) -- very clean and enjoyable, maybe a little less bass than I might want. I got them for $60 over on HeadFi. The FH1 is supposed to be quite good too, and cheaper. * Massdrop Noble X -- very smooth and enjoyable -- I got them second hand for $125 w/ the lightning cable * Cardas ear speaker em5813 -- these dropped in price recently. They are very laid back, maybe akin to the HD650? * iBasso IT-01 -- I generally liked the sound, but they didn't fit in my ears particularly well.
If you just want portability, you might check out the Audeze iSine 10. They might still be on sale for $149. They are an in-ear planar headphone.
I currently use a set of 1More triple drivers when I travel. They sound pretty good, and are at their best with a little power behind them. I currently use a VModa Vamp DAC/AMP and my iPhone X as a source.
I would rather have questions that can't be answered than answers that can't be questioned. - Richard Feynman
In-ear phones are a rather intimate purchase. My only concern would be warranty / returns.
I was definitely that way, then I thought about it a bit. It's worked reasonably well so far. I only purchase used if there is a significant price difference, and then I always pay with PayPal regular purchase, so I have protection for DoA. I figure that there _hopefully_ isn't too much that will go wrong with a pair of IEMs.
Then when they arrive, I wipe them with an alcohol wipe, even though every pair has been pristine so far. Note, my "N" isn't very large here. I've purchased 4 IEMs and two pairs of larger Mr Speakers headphones. One of those pairs did need to "air out" a little.
Good luck and definitely come back with your trials and experiences.