Of those, I'd suggest the Mosin. Rifle is inexpensive and so is ammo. I like the M44 carbine version best, but the full length rifle is a good weapon also.
History fails to record a single precedent in which nations subject to moral decay have not passed into political and economic decline. There has been either a spiritual awakening to overcome the moral lapse, or a progressive deterioration leading to ultimate national disaster.
If you think a strong military is expensive, think about what a weak one would cost