There are not any good free bots.... Other than the ones from rstrainers.com. They have a few decent free bots. Other than those there are none that I know of. I personally own bots from rsbots.net and I have never had any problems with them.
Recently a new free API was released by the RsBot production team; There have been mixed reviews to this with the biggest question being what are the best bots to run. RsBot is the program that runs multiple bots in one program so this is an excellent one for beginners. So I compiled a small information sheet for those who need help in getting started.
To get the Free RsBot API go to: http://adf.ly/CTMG and click download.
I recommend powerbot.org , has a huge community so they're are tons of bots. Some aren't of the best quality, but that's expected with free bots. There are quite a few gems though.