Exactly, look, I get that not everyone can afford a Pocket go or Bittboy or whatever. Then again the machines worth having are not that expensive. But like you I bought several machines trying to get a cheaper alternative and all I have now are machines that are almost nice or that almost work, but that have at least one glitch that really ruins it, and not just firmware wise.
Chinese manufacturers that make these are not gamers, they do not have the gaming culture we grew up in. As such, they don't care if the screen has tearing. Or if the audio is off or bad. Or if the d-pad is well nigh worthless or hard to use. Or if the button mapping is bad. Or the game does not save. Or if the frame rate is borderline unplayable. All they care about is that it "technically" runs it. At the lowest possible margins.
So you will end up with a machine that has all of those, or that does not allow more than 2 buttons to be press at a time... and the d-pad counts are separate buttons. Or one that only runs a couple of games of a system but not the ones you want. Or that actually runs a system but has the button mapping wrong so you lack the buttons to play them. Or that use a wired button membrane that lasts less than a year so you are left with a worthless machine.
Some of these can be hacked. But cost wise you end up spending more than an actual machine that just works with custom firmware. I'll use as an example my RS-69. It is a pseudo Bittboy clone but it is not compatible with CFW because the hardware is different enough that it doesn't work. But I did find out I can add L and R buttons to it. So I did. In the end it was way too much work, and while I did have a "working" machine, it still doesn't work with more than half the systems it says it does. Oh, they boot, yes, but 12-15 fps Sega Genesis and 15 fps SNES with layer priority issues (can't see enemies or bullets or the floor in some games) means I only modified my machine on MY time AND money just to have a slightly better machine.
Don't buy these useless systems. The Chinese don't put any effort because they says "oh they'll put some CFW on it and finish the job we did not". It doesn't work that way. If you want cheap, then buy a 20 dollar bluetooth gamepad and use it with your cellphone. You'll get better results that way.