Some info
The OP asked what is closest to the origional AKM. Anything from Century Arms are junk compared to all other AKM variants. My first AK was a WASR 10, it did what it was supposed to do, but compared to other AKM's they are junk and dont let anyone try to tell you that, that polished turd is anything other than that.
Here is a link to everything you need to know about buying an AK 47 here in the USA what to look for and such.
http://www.ak47world.com/rifles.html
The best place to get the best price on an AKM is at a local pawn shop. I just purchased a excellent condition SAR-1 for $350 out the door. If need be I can scan the receipt for the nay sayers. And yes a SAR 1 is an excellent AKM copy because they were actually built at the former Soviet armory.
One of the BEST 'Real Military Arsenal' AK's EVER imported into the USA (Milled-Receiver & Steyr Hammer-Forged Barrel) - a REAL Arsenal of Bulgaria (not from Arsenal Inc. of Las Vegas) SLR-96MB (Factory Muzzle Brake model) - that once sold for around $500 in 1996 !
DON'T get 'Suckered' by the New Crop of Yugoslavian M70 'PAP' AK-47's which are PRONE to 'Catatrophic FAILURE' due to importer MILLING OUT the former 'Single-Stack' Yugo PAP M70 AK's to take Hi-Cap Mags - but the 'PAP' has a Narrow Trunnion - that when opened to accept Hi-Cap Mags - make the Rifle considerably WEAKER in the Critical Trunnion/Chamber area that sees the MOST STRESS of an AK-47's firing/usage cycle !!!
As Norinco & Poly-Tech of China build EXCELLENT AK's, and so does Hungary with their SA-85M AK's by F.E.G. (not AMD-65 'Kit Guns' by Century...), 'Real' Yugoslavian AK's - imported by Mitchell Arms of Santa Ana, CA in the 1980's, Egyptian Maadi AKM, ARM, RPM & RML models only (not the MISR & MISR-90 'creations' by Century Arms...), 'Real' Bulgarian AK's like the SA-93, SLR-95, SLR-96, SLR-101 & SLR-105, and 'Real' Romanian AK's like the Intrac MK-I (AK-47), MK-II (AK-74) & early SAR-1, SAR-2 & SAR-3 Rifles !
If the WASR-10 functions OK w/o 'Failure to Feed' or 'Failure to extract' problems - then it's worth $500 to some retailers - as many distributors are ALL SOLD OUT of this less-than-desirable AK-47 w/o dimples on its receiver for proper magazine alignment - as the WASR-10 tries to compensate for this with defeciency by having pieces of sheet metal welded into its magazine well - (see Google & You tube for more on issues SOME PEOPLE have with WASR-10 AK's -
http://www.youtube.com/watch?v=m6H_sw-YKOc ) !!!
Still, besides the numerous problems that SOME have with WASR-10's - it's the LOWEST-PRICED AK-47 on the market & many Gun dealers & their 'victims' (uneducated buyers) ignore the WARRANTY NIGHTMARES that others have had with Century's WASR-10 Rifles - as some WASR-10's can be OK ?
The problem with Century Arms - could be a gamble with your time & your $$$ (that you won't have with a Norinco MAK-90, Hungarian SA-85M, or Bulgarian SA-93, SLR-95, etc.) - because even if the WASR-10 is new & the WASR-10 has problems - you won't get a new rifle from the FFL dealer who sold it to you if the rifle has problems & if the WASR-10 is used - how much $$$ do you want to spend for a gunsmith to fix the WASR-10 if you have no warranty ???
Also, on the other end of the AK spectrum - pictured below is a Russian Saiga 'IZ series' AK - that we constantly hear kids & others say, "I saw a 'Real' Russian AK-47 for $350 OR $400 or so..."
Oh really !!!
Unfortunately they're unable to accurately compare Sporter AK's like the Saiga IZ series (pictured below) to realize that after they convert the non-pistol Grip Saiga IZ AK-47 (pictured below) to have a standard Pistol Grip & standard or folding stock AK-47 buttstock & pistol grip (over $100 in most cases - which then makes their $350 bargain cost over $450...) - they'll still have a non-standard AK-47 that WON'T ACCEPT Standard AK-47 Mags/clips or drums - as special Surefire 30 round Mags COST OVER $40 a piece to fit in the Saiga IZ series AK-47 pictured below !!!