I have two SAR-1s, two hi-cap WASRs (looks like an SAR but doesn't have the dimples in the receiver above the mag well -- these were 10-shot low caps that Century milled out to accept hi-cap mags, and function flawlessly), and one Bulgarian SLR-95. For your needs, I would agree that the SAR or WASR hi-cap would be the way to go. The SAR is essentially an AKM-based weapon, stamped receiver, and will accept virtually all Euro-Combloc parts for "stamped" receivers.
Just take your time examining the weapon and pay attention to the vertical alignment of the front and rear sights and the gas block. Many of these have sights that are canted L or R a bit, and the fix is rather involved since removal of the front sight base pins can be difficult. It is best to be selective when you buy, and have it right the first time. Usually the canted sights don't affect operation, but if you are like me, the cock-eyed sight picture drives you nuts. You can avoid being one of the posters on another board that write "I bought an SAR and it has canted sights, what do I do?" Shouldn't have bought it in the first place.
As far as mags, they are very inexpensive at $10 ea. give or take being new or used and what the dealer is asking. I prefer 30s as they are very common and do not project below the weapon as far as a 40 rounder does. I bought several 20 round Hungarian mags from Ivanhoe's (www.ivanhoeoutlet.com) for $10 ea to use for bench or prone firing. Using a 40 round mag for bench or prone is extremely impractical unless you dig a small foxhole for the mag. :)
Many have bought SAR-3s because they are compatible with the AR ammo. SAR-3s have had their share of unique problems, including chambers reamed to incorrect lengths (aka incorrect headspace. Too long and the case head separates, too short and the bolt won't close reliably with some ammo). Another issue is that the hammer face is not modified properly to strike the shorter .223 bolt squarely. www.akdude.com has correctly modified hammers. Also, the SAR-3 is picky about mags and will feed only with properly modified mags or with the steel EG "Wieger" mags available from Interordnance, something like four in an EG pouch for $50, may be more or less. And SAR-3s also are prone to misaligned sights.
For a first AK, a select SAR-1 and a half-dozen 30 round mags is a outstanding package. 7.62 x 39 ammo is at the moment $80 to $100 a thousand depending on dealer and shipping. You could spend $450 on an SAR-1, six mags, and 1M rounds with a bit of selective shopping.
Good luck!
Noah