Well if you have Burnt fish from skilling, or Leather parts such as coifs and Hardbodies from training crafting. Also buckets, bronze shields, Red Spider eggs also work to some extent.
Pretty much just accumulated junk, F2p doesnt have junk inflating methods.
i got a starter pure 50 tt 57 str 1 def 60 range 15 pray from quests 45 mage 50+ non combat stats 56 hp 40 quest points 30 days membs 800k bank all info can be provided but i got no junk hopping u mite got an acc to swap ?