If you've read some of my reviews of Thai food before on this page then you may have noticed that I have a weak spot for inexpensive places. Indeed in Thailand there often seems to be no relation between the quality & tastiness of the food and the price. Price relates more directly with 'ambience' than with the actual food served; like a restaurant that is in a prime riverside location, features live music, air-conditioning, plenty of waitresses, a large menu, table cloths and so on will be priced higher than a small road-side food stall or mom & pop restaurant with plastic plates and forks and spoons so thin they bend out of shape by merely looking at them. Really, anyone can be a Uri Geller at these places! Kidding aside, the actual food at these cheaper places may very well be as good or even better than at the posh pub-restaurants.
No such claims about 'the best' for this place today, but MAN is it cheap! "Kuaytiow Saam Baht" (Three Baht Noodle) restaurant does exactly what the name suggests: Sell noodle soup at prices from Grandmother's era. Admitted, the portions are seriously small, but then again sometimes you don't want to eat all that much food, and it's excellent when you're on a diet. Or you can add some variety and add more servings or dishes, as they also do Khao Soi (Yellow noodles in a curry soup). What a difference the size of this Khao Soi bowl is with the shop that I think does the best in Chiang Mai, see: http://chanchao.fotopages.com/?entry=64940(Khao Soi Techno College (Mae Jam Paa))).
Anyway, when you're paying a grand total of 13 baht for lunch, then who's complaining. This shop, 'Kuaytiow Saam Baht' is on Doi Saket Kao road, that's the road that runs North of, and more or less parallel to Kaew Nawarat road. If you come from Rattanakosin Bridge then you will find the shop on your left hand side. Or when coming from near the Arcade Bus terminal and doing a right-left at the first traffic lights on to Doi Saket Kao road then it's on the right side of course.