Fire Arrows scrolls are pretty cheap for the benefits they give (as long as you remember to refill yourself between quests so you don’t run out in the middle of a fight)Not sure if anyone else does this for bow builds, but I'll do 3 wis and then dark hunter - using the imbues from wis and just upping the imbue dice where I can, and taking the arrow creation from conjure arrows in horizon walker, or go to 5 in wis and conjure fire arrows. Everything else boils down to increasing ranged power and personal defenses and feats. weapon focus, point blank, etc.
The OP asked for a "good bow build for levels 1-20".Ranged is so over powered in the current meta that i think they are all good.