If you have a Whole Foods nearby, the Three Wishes brand of wines there (I think a WF exclusive) are amazing for the price of $3/bottle. We got a bunch of it for our wedding, and it was as good some $15-20 wines I've had. I think they have it in have Merlot, Cabernet Sauvignon, and Chardonnay.
Also, Black Box wines are awesome for the price as long as you'll drink the equivalent of 4 bottles of 1 variety in a month or less.