In F2P, sadly to OSRS gold say there's not a lot of variety. The most likely drop will come from a repulsive, which would be the corrupted dragon scimi. However, aside from that it's only coins that you could not even place in your cash pouch.
Also, if you happen to have the revs gang around you, the odds are stacked against you 80% of the time, unless you have at least a decent amount of prayer left... which you can't even charge for, unless you use a twisted bird neck and eliminate the ankous within the next chamber.
The main profit from killing in f2p is probably Lesser undemons Cockroaches or perhaps Ankous at 70 defence or 70 range when you securespot or spot Greater Demons but it's not really advised because of their location located away from banks. Most people resort to dungeoneering to f2p to eliminate several bosses.
The first thing to remember is that it's best to go with Ranged and Melee, if your melee skills are near acceptable (80+ Attack, 80and Strength). Magic is a possibility - it might prove to be effective , however it's generally costly (200GP per cast with the Polypore is still costly, however, it's not that expensive). The second option is to use armour with a higher defense until you're proficient in praying at TDS before switching to Void.
How do you become proficient in prayer switching? If they're attacking with melee and then start to unleash, then you need to determine if they are from range or mage. If you can guess correctly then you're good, but if it's wrong then you are likely to take damage before switching... Let me know if I'm mistaken... It's what I read on guides that i haven't visited there, or buy 2007 runescape gold completed the quest yet.
