Got an older bike setup with a single front chainring and 7 speed freewheel. Would like opinions on what's the best chain keeper to install so I quit dropping my chain (generally to the outside)! Woul like something on the smaller side if possible, but whatever keeps it on is what it will get. Or I'll just hack up a front derailer and use that if I don't like the options.

RU cheap?

Chain guard made perhaps out of an old 5t larger chainring
or just an old FD with the limit screw adjusted to sit over the 1 chainring without
a cable hooked up.
.

What cranks are ya runnin? Single Speed Chainring or was it a Chainring that was once a part of a triple?

https://www.amazon.com/Dimension-Chai.../dp/B001CK2IPC

These aren't particularly cheap but they have a clean look to them. They're great on vertical dropout SS conversions. hth

It Sounds like your chainline may be "off", could be caused by bent frame, or a short BB spindle. teh cahin keeper is a fix but you may other problems

A chain keeper may be a Band-Aid but here's a nice-looking one: https://www.paulcomp.com/chainkeeper.html

It's a truvativ 50/39 crankset with the smaller ring removed, 7 speed cassette in the rear a 11 or 12-28 (forgot). Nothings bent, chainwheel/chain/cassette/RD all new. Could be the chainline is off, I did put a less wide BB in it. I'll have to check, but looks to be a nice straight chainline when it's in the middle of the cassette. Guess I should string the frame and make sure it's straight. Winter's here, so plenty of time to wrench on the nice bike. Thanks for the links and answers
Probably a SS chainring would work better too, nice full/tall teeth.