A very cheap method is cursing. If you buy a a mud battlestaff, each curse only costs a body rune which is 5gp each.
The fastest way without teleporting would probably be fire-bolting on lesser demons at karamja volcano, using the safespots.
If your looking to make money, then either telegrabbing wines of zamorak at the chaos altar, or making teletabs would be your best bet.
~OfficialMobster