Higher price gets you better fit and finish, and better furniture. Milled is more expensive than stamped, and to some it looks nicer, but stamped works just as well and is lighter.
I had an inexpensive SAR-1 (Romanian AK) for years and liked it, but the finish was rather "industrial" with plenty of rough edges. From a reliability standpoint, though, mine was perfect; I shot perhaps a few thousand rounds through mine, using milsurp steel magazines, and it never had a single failure of any kind. A more expensive AK will have a smoother finish, and may be somewhat more accurate due to a higher quality barrel. Some of the nicest ones come with MIL-STD-1913 rails on the receiver for mounting optics; in my experience, adding an optic is the single best thing you can do to make an AK more accurate and more fun to shoot.
Another question is caliber. Civilian AK-47 lookalikes of course shoot the 7.62x39mm cartridge, but there are also the 5.45x39mm rifles (AK-74 derivatives) and even some in .223 Remington/5.56x45mm NATO. Mine was 7.62x39mm, but if I were going to get another, I might go 5.45x39mm if I found one in my price range, as they are lighter and arguably a little better suited for HD. .223 AK's have a wider selection of good ammo, but are reportedly a little less reliable than the 7.62x39 and 5.45x39 guns.
Also, there is the choice of muzzle device. "Authentic" looking AK-47 derivatives often have a slant brake on the muzzle, but these are bad for accuracy; I'd much rather have an A2 style flash suppressor, or even a bare muzzle (mine was a 2002 import so it had a bare muzzle). AK-74 style brakes don't hurt accuracy but do make the rifle louder, so think through what you want. For me personally, I think my dream AK would be a nice 5.45x39mm built on a light 1mm stamped receiver with an Aimpoint, a light, and a Vortex or Blackout flash suppressor, but there are a lot of good choices, and I thoroughly enjoyed my $379 SAR-1 with a Kobra optic.
