If you are looking at vintage 10 speeds, couple tips to spot a better equipped bike.
1) Look for downtube shifters, not shifters up on the stem
2) Make sure the rims are aluminum
3) Look for 3 piece crank(not cottered which has a small bolt sticking out of the side of the crank arm). The Varsity has a 1 piece crank.

This should get you in the mid range and up for most 10 speeds from the 70's/80's. $150 should get you something ready to ride.