Best inexpensive Sancerre and Sauvignon Blanc
Doesn't that depend upon how one defines "inexpensive"?
Gerard Boulay's Sancerres are outstanding, and at $21.99, I find it to be an excellent value, playing (as they say) "well above its playing weight" -- especially compared to the approx. $40 Cotat . . . The same can be said for the Sancerre from Thomas-Labaille. All three of these producers are in Chavignol.
From New Zealand, Isabel is $15.99 or so.
From California, Mason Sauvignon Blanc is still +/- $12.99.
Finding Sancerre for under $15 is getting more and more difficult. If you still want Loire Valley sauvignon blanc wines, however, you'll find more wines from Quincy and Reuilly in your price range. But wines from those appellations aren't easily found unless you live in a large enough city.