Can you tell if it was made in Japan or Korea? Early Kingstons (beginning circa 1959) were small-sized acoustics made by Terada Trading. Kingston electrics were made by Teisco until Kawai, which had taken over acoustic production by the mid-60s, acquired Teisco.
Kingston didn't start making larger-sized instruments until the early 1970s. There are not a lot of detailed records on Kingston, which was a brand owned by Jack Westheimer, so much of the info comes from Kinsgton catalogs, if you can find them. Around 1974, one such catalog showed Terada-made acoustics once more. By the mid-70s, production costs were rising and so production began to move to Korea. Jack Westheimer founded Cort, which was based in Korea, and guitars were made there exclusively from about 1977 until 1983.
The Kingston line disappeared for a while, then returned, but the instruments were lower-quality and made in unknown Asian factories into the 1990s.
Value will depend on condition and on where and when yours was made. If you have a circa early 1970s Japanese model, the build quality is probably decent, but acoustics just do not have the value of electrics. Some of the '60s into early 70s electrics from Teisco, Kay and others are superior to the CBS-owned Fenders from the same period, and when a real guitar player stumbles across a good one, they keep it. But that is very hit-or-miss.
Not the same with acoustics, unfortunately. I have a very nicely made circa 1971 Ensenada acoustic from Japan (imported by one of Westheimer/Kingston's competitors, Norman Sackheim/Norma). I picked it up from the curb in an almost-new Roadrunner case. Normal action, no issues with it whatsoever. I would be lucky to get $60 for it and it's a nice instrument.
That doesn't bode well for you. If you have a nice Japanese guitar, maybe you could get $100. But if it's a cheaper 1990s model, and it doesn't have high action or intonation issues (fixable but not worth fixing), maybe $25 - $30? If it has issues, it's a wall-hanger.