How much is 99 mage

This all depends what you are trying to do and the level you currently our. The cheapest option is high alchemy by a long way and you can gain money back depending on what you alch. Level 55 is the required level to high alchemy and to get 99 from there you will need a fire staff 197,967 nature runes andallot of time. from the date which is 4/10/09 the nature rune currently cost 304gp each and recently dropped 6gp so lets do the maths 197,967x304=60,181,968gp short terms 60m. There we go the cheapest option is 60m but this can easily change if it drops 1gp you are already saving yourself 150k+ so it is advisable to wait for a drop if it raises I'm sorry. Thanks i hope this helps you out a bit comment back if it does :D