My guess on the age is approximately 1984. Gemaco started making some headway that year in the casino business. The High Sierra re-branded near that time also. Many times you can find the date written by casino personnel on the inside of the tuck flap, but they look sealed. The High Sierra eventually changed the card design and went to a plain white back with an oval, that change was made in about 1987 or so - the plain design are still Gemaco. I have included a scan.

Price $5-6 would be fair.