Around here Ribeye is often on sale for $4.99 lb. Safeway has the best!! So.....1 1/2 lb. would be roughly $7.50 ! :)
Call (or go to) your local market and inquire what they are selling it for per pound.
It fluctuates wildly. I've seen it anywhere from $1.99 per pound to $6.99. Your best bet is to save up and buy a quarter or half of beef from a small ranch. Then you get all the cuts for a set price per pound, and better beef too!
It depends what part of country you are in. I'm in Chicago, seems to be a bit more reasonable here then in the other 3 directions, E,W,S, I'm North guys! On average, not on sale, mid quality, 12-13.00/ LB.on sale 8-11.00/LB. Really good quality on sale should run 10/lb hope that helps.