By the Viet Vegan
Link to Homemade Vegan Vietnamese Pho recipe.
GV comments: I have yet to try this recipe, but it looks the most authentic of the vegan recipes I've found.
Timing: She says it takes 2 hours
Affordability: There are some specialized ingredients, so likely in the $10-15 range
Nutrition: Whole-food unprocessed except for the noodles are made from white rice flour, not brown rice flour