Someone somewhere would easily pay $125 for it as-is. From your standpoint - if it fits you - the gamble is how much $$ do you need to sink into it?
Check the cranks & sprockets closely, do the cranks appear true when rotated from above? Are the bearings smooth, but not loose? How much wear do the chainrings have? The spaces between the teeth should be semicircles, not ovaled out.
Is the chain rusty? Do the rear sprockets show any wear?
Are the wheels true and round? Are the tires in good condition? Do they still have any air in them?
Do the shifters and brakes work smoothly? Do the cables look frayed? Do the brakes seem to grab well?
How are the bearings in the head tube? Are they tight but smooth also?
Stand in front of the bike & sight straight down the top tube towards the rear wheel. Does it appear to be centered and straight in the frame? Does the whole rear triangle appear to be bent and/or shifted to the side?
Now stand over the bike looking forward over the front wheel. Is it centered between the crown of the fork? Look at the fork from the side, do the fork legs look bent backward at all?
If the frame & fork aren't bent it will make a very nice vintage ride. However, depending on what repairs/parts/maintenance are required it might not be a cheap ride.
For example, if it needs tires & tubes you're probably at $50 minimum and can quite easily go over $100. New shifter & derailure cables - $20-$30. If there's any problem with the crank or bottom bracket bearings...well you might find a good deal on some used parts, but you also might spend a couple hundred there.
If you can find a used seatpost that fits it may only be $10 or so, but seats of any quality/comfort usually aren't cheap. Same deal with pedals.
I'm not trying to steer you away by any means, just realize that you could end up with $400-$500 into this pretty quickly if it needs much and/or you don't find deals on any good used parts for it. Would it be worth putting that much into? If it fits you and you like it, absolutely!