I've been very happy lately with inexpensive wines from Valle de Tulum in San Juan. Las Moras's (Dada, Love, etc.) were already mentioned here. Another big winery there is Graffigna. Did someone find their Pinot Grigio at a good price? There's also Casa Montes. I liked their Ampakama Torrontés, Viognier late harvest, and Fuego Negro, given their very-low prices, but I didn't enjoy a few other inexpensive reds and rosés they make.
Apparently, San Juan is still regarded as a producer of low-quality wines, and some of its wineries even avoid stating the place of origin on their labels. But that's been changing, although the step forward in quality has been taken about a decade later than in Mendoza.