Check the frozen food case at Makro. Near the ice cream and frozen desserts. I also like roti and purchase it there regularly. Just put the roti on a dry skillet over low to medium heat and in a few minutes it puffs up and is pretty good for a packaged product. After turning, the second side takes much less time to cook than the first side, beware of burning. They have original roti and some flavored ones like garlic & herbs.
If I remember correctly, I've seen it in the frozen food sections at Tesco and Tops as well.
There's a roti cart in front of the day care/preschool next door to the driving school you recently inquired about. The guy is there between 1530 & 1630.
Yes, I have found the frozen ones acceptable. I am lazy; I don't even bother with heating them on a skillet; I just microwave them. I too have eaten them in Nong Khai from the carts, bur can't find any in Udon. May be I will get one to sell from in the Nong Prajak area.
Going off-topic here: we did contact the driving school, and my lady-Thai will enroll there. But, first we would like to buy a pick-up, a Toyota Vigo, or a similar one with a four door configuration. We would prefer to buy one that is built in Japan, not just made by a Japanese company. Any comments?
a good one at Soi Nung bua and Prosi rd, if you were to try to continue across prosi rd, he sets up right on the SW corner, heading into town. good stuff, actually clean for location, doesn't set up till 3 ish, for after school crowd, and stays busy. 20-25 bht, nice size and tasy, the 5 baht extra is for chocolate added to my usual banana roti. which i've stop adding.