I have the same bike! Well, almost... yours has a cotterless crank; mine is cottered. The cotterless crank was on the "Super Mirage" in 1975 when I bought mine.
Somehow I managed to keep the bike, and a few years ago I serviced all the bearings, changed the bars and put new brake levers on it. It's actually a delightful bike to ride. Friction shifting 2 x 5, a traditional 10-speed. The fork and front wheel were damaged by a drunk landlord about 30 years ago. The replacement fork is chromed, and the new front wheel has an aluminum rim, so the braking is much better.
They're right about the tools. You might not recover their cost by fixing other bikes, but the satisfaction you'll get from doing the work yourself may be reward enough... it is for me!
The overhauled Mirage. Paint is a bit rough, but the steel frame makes a comfortable ride.
Alloy bars, Paul brake levers and Ergon cork grips.
Original Suntour VGT Luxe derailleur.
Original head tube badge.