Easy way to determine value is to use the Search tool in the top bar of this site, then choose "advanced search" and search for "Lakland 44-94" in the Classified section. You should be able to see all the Lakland 44-94 that people have posted for sale here. This should give you a good overall value for you instrament.
Generally, a used instrament will go for between 50% and 70% of what you purchased it new for (depending on condition). Vintage instraments are a whole nother can of worms.