Between an unknown cheap amp with no feedback nor measurements taken by exhaustive reviews you might as well get a cheap portable DAC-HPamp from a reliable manufacturer.
If you can stretch your budget, there's the Pangea HP101 (Amazon and eBay). I never paid much attention to it before when it was $249, but my brother came across it and he and our Dad chipped in to get it for me when the price dropped. Surprisingly good. Tube has a bit of noise with low voltage line signals (none if you use its own DAC). Tube replacements are
not an easy DIY job though - you can't just pull it off and push in a new one. I have a Mullard 12AX7 lying around that I decided to keep to use in it at some point. However as much as it's a great amplifier the DAC is problematic on the software side - on Windows it only works with player apps (YouTube and others on the browser come out of the speakers for some reason; this doesn't happen with any other DAC), but works without any issues with my Android.
Another choice is the Fiio E10K, but it's USB-powered so just note that it has some limitations with harder to drive headphones.