Forbes has a recent article of on good, cheap wines, but none came in under $10/bottle. Food and Wine an The Wine Curmudgeon have a few bargains, all around $10/bottle.
R. Muller has been touted as drinkable. Their Riesling sells for $24, but that is only for three liters, or about $6/equivalent bottle. Here is one list, but they're still too expensive for me. Epicurous.com has their top five, but, still on the high side. My all-time favorite is Peter Vella Chardonnay. Five liters for $16, but sometime on sale at Long's for less than $10. That would be the equivalent of a two buck chuck's. The beauty of this system is that the wine never contacts air. You open it, close it, and it's good in a refrigerator for a month or more.
I have yet to find a really excellent red boxed wine that is cheap enough for me. There is "champagne" in a can: Francis Ford Coppola 6 ounce Blanc De Blancs named Sofia. But I'm still on the search for a really terrific and low cost 5-liter box red wine.