The best item which is also relatively cheap are the Bandos boots.
The Ancient Mace from the goblin quest series, and the Granite mace from Chosen commander will also suffice.
There are only 6 items that cover Bandos, the Bandos armour, Ancient Mace, Granite mace, and the Bandos Godsword.
A bath in the bandos pool in Oo'glog is free. However, you need the quest "As a first resort" and the effect of the pool wears off after about an hour.