In my experience, it seems as though the price of M1 Rifles has begun to level off a little bit in recent months. There was a time (not too long ago) where people were actually getting $2000 for rebuilt shooters in the EE but buyers seem to have smartened up a bit.
Generally speaking, nice shooter grade examples seem to sell anywhere from $1000 to $1500. For a rifle to be worth more than this, it has to be something exceptional... Unless of course it was built in the garage of the great Squinty. Such rifles are worth considerably more as his superior knowledge and intellect gives him the ability to fabricate perfect rifles that the rest of us plebs couldn't even dream of waving a stick at.
I apologize for digressing... Going back to your initial question, the price of an M1 Rifle is dependent upon a number of factors. Condition, originality and rarity are amongst the most important determinants. Any original rifle, regardless of manufacturer will be worth more from a fiscal perspective than its rebuilt counterpart. I am of the opinion that an original wartime example manufactured by Springfield or Winchester is typically worth more than a post war example but obviously there are certain exceptions. Collectors seem to pay premiums for M1D sniper variants, correct IHC manufactured examples as well as Springfield rifles which fall within the 6 million serial range. These select post war variations are typically comparable in price with the wartime examples. They will almost always run north of $2000 ... and in certain instances much more than this.
Taking this one step further, I'll very briefly touch on the rarest of the rare... If by some amazing stroke of luck you came across an original gas trap rifle, you should not be surprised to see a five figure price tag attached to it (I've heard of them selling for up to $50,000 in the United States). I assume the same could be said for an authentic M1C Sniper manufactured during WWII. To the best of my knowledge, only 7,971 of these M1C sniper variants were manufactured in late 1944 to early 1945 and of those, 4,796 were subsequently refurbished in the early 1950s for use in the Korean War. After crunching some numbers, that leaves us with a potential 3175 possible M1C rifles out there... So if you find one of them, I strongly suggest that you do whatever you can to secure it. Take out a loan if you have to and if your wife won't let you, for the love of god at least think about giving me a call!
So, to answer your question, an M1 Rifle can be worth anywhere from $1000 to $50,000 depending on what it is.
- Chris