The S&W model 28 is a N (large) frame .357 Mag, which also allows for .38spl. The Magnum cartridge is slightly longer then the .38. The cylinder is chambered accordingly.
The S&W 28 is the 'No Frills' version of the S&W 27 .357 Mag. The 28's finish is a matte blue (black). She comes in 6" or 4" BBL.
Pricing is hard to tell at the moment after all the frenzy on the gun market. The 28 was discontinued in the late 80's as where the 27 and S&W 29 (.44 Mag or .44 Spl) within the same time period. All of which are N frames.
That means for some these are collectors at the lower end. Than it depends where you are located. The 4" bbl usually goes for a bit more then the 6" bbl. Minimum used to be $300 (I got word from a fella in NM, he found a 6" in very good condition for $300 shop price, last year)
Maximum I heard of was $750 for a 4" in very good condition in Northern Cali.
A good condition 27 or 29 would be more in any case, except you find one from a private party.
There are many other S&W models out there to be considered K/L (medium) frames and even J (small) frame are out in .357 Mag/ .38spl.
If you want more info on S&W wheel guns, just ask. You can browse this website for current models of all different makes and types of firearms:
https://www.galleryofguns.com/genie/default.aspx