You mean you?re interested in buying one as a good player & maybe with collector value? Or do you mean from a business point of view, ie to make a profit on sales? I guess they?d be different criteria.
OK, well as Bobastic says, this is a vast subject, so following is something of a generalization & purely my personal take on things, but .......most desirable by far, & consequently highest price, are the original Springysound models from 1978 to 82 (?Springysound" decal on headstock). These have so-called ?spaghetti 7okai? logo (ie thin script decal with the ?T? of Tokai written as a backward number ?7?). Until 1980 they had proper 7-digit serial number stamped on neckplate, ie with same date sequence as the Gibson copies (see Registry under Gibson copies for explanation of date codes), early ones also had the model number impressed into the end of the fretboard (again like the early Les Paul copies, Reborn & Reborn Old). Models ranged from ST50 to above ST100, though I?ve never seen a model above ST80. Most examples are sunburst (desirable finish).
After 82 the model name changed to ?Goldstarsound? and the logo was changed. At first the logo briefly became a fat script 7okai style for about a year or less, then in 1983 it changed to a completely different black printed ?block? logo. Then in 1984 the logo changed again to the sort of style you see today, ie a sort-of fat script but with a normal shaped ?T? (not a backward 7). The guitars don't really have a serial number, instead the neckplate has 5 or 6 digit number identifying the style of the guitar (number identifies which US Fender model is being copied...same necplates/numbers on 80-82 Springy's), again see Registry for info. You see a lot of Goldstars for sale, & sellers almost always claim they?re ?1984-85?, but really there?s no way of identifying the date & sellers are just trying to add value by making the guitar seem older & more vintage. Goldstars are good guitars, & early ones are probably the equal of original Springysounds, but price is 50%-60% less than a Springysound. Examples in range of solid colours as well as sunburst.
Silverstars are copies of the 1970?s US Fenders, ie with large headstock & bullet truss-rod. That style is far less fashionable than the Springy or Goldstar shapes (copies of 1950?s & early 60?s style Fender), and values are consequently lower than Goldstar. That's not to criticise the guitars in any way, they're eprobably fine (I've never palyed one), but just that current fashion dictates a lower price. Again you see a lot of sellers advertising these as ?1978?, but as far as I know they weren?t made until early 1980?s and probably in production for less than a decade. Most examples are solid colours, which is again generally less desirable & less value than sunburst.
Apart from these there are also a few Special Edition models, often with self-coloured headstock (ie same as body colour) and often in metalic colours (metalic blue & shorline gold)...these are quite rare, mainly 1980's Goldstar models, and quickly becoming desirable with rising prices.
Ian