Irksol

Irksol sells Ruby rings in Zanaris market for 2,085 coins. He is an Otherworldly being.

It's very common for players to train magic because he sells ruby rings in such low price that you will only lose 20 coins per high alchemy even if you buy the nature runes.

It should be interesting to note that Irksol says there are over 2,400 planes of existence in RuneScape.