Cheapest way to lower that car will be to cut 1 coil off each front coil, and put a set of lowering blocks between the rear axle and the spring. If your OK with the brakes, cut the coils and add the lowering blocks and drive the thing. Lowering blocks will not alter the rear ride at all, just don't get carried away, 1" to 2" max. Cutting one coil off the front springs might make it a little stiffer in the front, but probably not much, as long as the current springs are not shot now.
Air bags and the related hardware is an expensive way to lower a car.

For me, given a choice of spending money on lowering a car or improving brakes, the brakes win hands down. I understand the concern about spending money when things are tight, spend the money for safety equipment rather then on how the car looks. 50s brakes suck compared to modern brakes. Gene