Methods for training experience are either fast and expensive, or slow and cheap.
In Runescape, You receive 65 Magic XP for every High Alchemy spell that is cast.
Magic Logs give 303 xp per log when you burn them.
Falador teleport gives you 48 Magic experience.
Depending on how efficient you are, about 100-120k per hour.
Make some money on the game and spend it on some runes, and cast the spell you can cast and you will get magic xp for casting it on enemies.
Same as for level 99 in any other skill. About 13 millions.
XP is not calculate when you kill a monster, but every time you hit it. You get XP for every damage point you inflict. In the case of magic spells, you also get a basic magic experience, just for using the spell. I am not sure about ranged.
13,034,431 xp
101,333 xp.
Yes, you get range xp.
Casting high alchemy can grant up to 78,000 magic experience per hour if casted efficiently.
Elvis is first on the list for Total XP.