Is there a cheaper, but decent alternative to the jigging rap? 

Thanks

I did pick up some Berkely snap jigs but I haven't tried them yet.

Those Snap Jigs catch fish.  I use a small fluke on them.  Also in that family of lures are  tail spinners like the old little george, blade baits/silver buddies, or jigging spoons.  War Eagle makes a great jigging spoon that WM sells for pretty cheap.  Good luck man!