Luckily, I was introduced to a replacement for my wino days in Europe: Mont Clair Red Wine. Though I'm no wine expert, I know enough to say that the price is right on this wine--especially in Chiang Mai. Despite its qualm of being a boxed wine, this South African wine acts as a perfect table or every day wine for casual wine drinkers. Obviously there are better options; obviously these have higher prices.
A 5L bag of Mont Clair will run you 950 THB, approximately 142 THB per bottle. As far as I know, a glass of wine at most restaurants will be at least 80 THB: for the habitual wine drinker, this provides significant savings. Another advantage is that the box easily can fit in your refrigerator, making it a perfect option if you only want a glass or two.
Though drinking a glass with a friend is advised, Mont Clair makes a glass of wine a night possible even on your own--no need to leave an unfinished bottle lying around. Purchase at 7-11, Tesco, or any local licquor store.