Can I make an incredibly cheap guitar sound decent?

I've cleaned up, set up, and resold dozens of those yard sale specials. Sounds like a great project if you want to spend a little time on it and learn something in the process. I was usually able to show a small profit on that sort of thing, or at least make it pay for itself and maybe a book or some tools or supplies.

Intonation is very easily adjusted if you have movable saddles and an electronic tuner. I'm not sure you actually mean intonation (the ability to play in tune all the way up the neck), though. Try it plugged in and with fresh strings. Playing it unplugged doesn't tell you anything about the pickups, and you don't expect an electric to have good acoustic tone.

If I were you, I'd pick up a copy of a good guitar repair book, say Dan Erlewine's, and have some fun. Or else sell the thing to someone who wants the practice.

P.S. pics would be nice. There's a market for some of the old cheap stuff, so don't do a Pete Townshend without getting a second opinion.

You can try to make it playable, but good sounding will be hard. Decent, maybe with enough work. But it would be easier to just dish out more money for a decent 100-200 dollar guitar.

Fix all things wrong with it, INtonation, Bridge height, strings, pickup height, etc..

Well I wouldn't expect a $50 guitar to replace my number 1. But it's fine to have multiple guitars and enjoy them for what they are. My cheapest guitar was $85 used and my most expensive almost $5000 new, but I play them all. I'm not going to gig with my $85 Teisco, but I still have fun with it.

If you can't get the guitar to intonate properly, then it's not worth putting money into. Other guitars, if they are cheap and you enjoy playing them, then it's worth upgrading the pickups.

Well, the hardest thing is for whoever ended up paying money for the thing, with like the loss of a couple of really good pizzas. I wouldn't put a dime in it, but either screw it to a wall in whimsical decorating, or perhaps save it for a "Pete Townshend Finish". Here's a short review:

https://www.youtube.com/watch?v=3OV8csBIFX4

'Road band I worked with did this a couple of times, for the "finale", and the "crowd went wild".

Just be careful for the rest of the guys on stage.

EDIT: Yeah, JCR is right (as usual), Take your time and pick your goals.