>>4148
>That leaves me with darts and javelins I guess.

I recommend you use that PhD brain to think of interesting, unique and ingenious strategies that will be sure to amaze.

>How many [darts] should I buy?

Based on a typical battle, Bear's party used about 3-4 ammo each encounter. I relaxed the rules to allow all ammo to be looted back but if you roll a 1 on attack the ammo is lost or destroyed.

Darts are dirt cheep and light. Arrows are expensive and heavy.

Remember that darts will be used with dexterity. If you had Dexterity +2 and proficiency in darts +2, to hit would be +4 and damage would be +2. You will never have proficiency in improvised weapons so it's always better to use 1d4 darts than rocks.