There is a good selection of decent 3-9X40 scopes starting at $200. You can get an excellent 3-9X40 for $300-$350 Anything with more magnification is going to cost a lot more if of equal quality. You don't need more than a 3-9 on a 338 mag even at 500 yards and you don't need turrets. The high magnification scopes with turrets are meant for shooting small varmits at 500 yards. I don't think you'll be shooting ground squirrels with a 338 and a 9X is plenty for deer or elk at that range.
You want decent quality on a hard recoiling gun. If I were buying for me it would be this. Primarily because of their reputation to standing up to recoil.
http://swfa.com/Leupold-3-9x40-VX-2-...pe-P51800.aspx
Zero the crosshairs at 200 yards, the next 2 dots are for 300 and 400. Where the post tapers will be for 500 yards. This is surprisingly accurate and simple to use.
If that is too expensive a Burris FF-II offers the same reticle for $200.
http://swfa.com/Burris-3-9x40-Fullfi...ope-P7932.aspx
If you're sold on Nikon they are on sale right now.
http://swfa.com/Nikon-3-9x40-Buckmas...pe-P42255.aspx