You can cut the front, but the back is progressive wound, smaller diameter at top and bottom, means shouldn't be cut. I have seen people put stock Camaro springs in these cars, but it makes the ride really soft, more so than stock. You can get a full set for around 200.00 or jut buy the back springs and cut the fronts.
Not sure how low you wanna go, but a set of stock SS springs will drop you 1 to 1 1/2 inches. Also, if you buy a lowering kit for an SS then it is gonna be really low compared to your stock Caprice ride height.
I bought a set of used, stock Impala springs off this forum.
They cost me $80.00 for all four.
I did cut a half coil off the front springs and I'm very happy with the results.
Put the word out your looking for set. Someone may have some.