Cheapest+Easiest=Heat the springs. I haven't done this. I cut one coil out and used 2.5" drop spindles on my 69 Burb. For the rear I made a set of 3.5" lowering blocks and longer U-bolts. This allows you to use your stock shocks if you want to. The only trouble I've had with it is that the U-Bolt nuts will drag on an automated car-wash track.
The better way is arms or spindles and drop springs in front and drop springs/c-notch/shock relocator in the rear.
