Nice little slag-glass stag-motif table lamp , jcmurp .
If you use the search term(s) 'antique stag slag glass lamp' on the internet , you'll find out a fair amount about items like yours !!!
Carefully inspect the 'base' of your lamp to locate any possible signatures , marks & etc , since some marks &/or sigs can really boost the cash value of such items .
My knee-jerk response is that your lamp seems like it's from the early 1900's .
I have seen stag-motif lamps , in the past ten years (in the U.S.) , selling for $200 - $800 USD , depending upon the lamp & the location where auction/estate-sales were held .