wikiarms - click 223Rem - uncheck steel - uncheck reloads - CTRL+F and search for "62"
OR
wikiarms - search box = '62' - click search - results return - drop down for "Caliber" select 223
*Wikiarms has truly made my ammo searching so much more efficient. You can also setup email alerts so it tells you when ammo prices are good to go...
Search is particularly effective for stuff like 68-77gr OTMs and finding best prices there (FWIW, the Hornady 75 gr steel is the cheapest in these weights at $370-$500 per thousand; otherwise, you're looking at the PPU match brass case loadings in the 40-60 cent per round range)
The lowest 62gr brass is from BuyGunsandAmmo, and it's the Romanian Mil-Spec stuff (true milspec sealants etc) that jdubya87 mentioned. Should be the same stuff as the HotShot Romanian brass that's usually priced a little higher.
http://buygunsandammo.com/product/5-56-62gr-fmj-ss109-penetrator-sealed-brass-case$325 per thousand -- reviews I've seen have been good and the sealed ammo is definitely appealing.
Other good options:
-SG Ammo has the AMA Denex 62gr at $340/thousand -- believe it has sealed primer and packaged on (plastic) stripper clips and in sealed plastic so moisture proof regardless; bought a case but still sealed tight and haven't shot. Have seen it in Academy Sports, Walmart and elsewhere for ~$500 per thousand...
-Wideners has IMI 62 gr at $400/thousand ($479 per 1200)
-Wideners also has IMI 55 gr at $380/thousand ($455 per 1200, IMO this is the best 5.56 mil surp ammo deal going & accurate too -- up there with Black Hills)
-Not quite milspec, but moreso than their steel, but Wolf Gold 55gr has been running $310 per thousand. PMC, various Federal, PPU, Fiocchi, and Bosnian Igman (this 62gr) are in the price range too. Personally, I'd prefer the Romanian to Igman based upon what I've seen others post.
Remember that all if not most of the Lake City stuff isn't actually milsurp. You're lucky if the primers are sealed and the case necks rarely have the milspec tar sealant. IMI stuff at Wideners is all actually milspec that I've seen. Occasionally, you'll see independence or winchester IMI on sale, but that's rare.