No, somtum every day is a Thai minimum wage or an Isaan less than minimum wage earner. On a farang teacher's salary you can afford to eat international food a few times a week (eating out too, na)!
Actually, cooking at home, you can make international food cheaper than Thai food made at the market. I make Indian curry, Lebanese hummus, European soup, muesli, Scots porridge oats, spaghetti pesto or carbonara, and it is FAR cheaper per portion than, for example, a prawn fried rice or papaya salad meal bought from the market.
I mean 500 grams of lentils, chickpeas, oats, or pasta costs less than a single serving of fried rice or noodle soup from the street.