To get arrows as a F2P, you have to buy them, from archery shops or the Grand Exchange. There are also ground spawns, but these aren't reccomended there are also several monsters that drop arrows i find the ones in dougeon under barbarian village to be the best place to get arrows. if you want bronze and iron mainly iron though go kill the minotaurs on the first level if you want steel kill zombies on 2nd level for mithril kill catablepons on 3rd level (not recomended though due to strong and strength reducing monsters) for adamant kill ankous on 4th level. i recomend that you only kill zombies and minoutars because they are low level and have higher drop rate.