If that is true, then I don't see why NIN is demonized as an expensive job.
Lets take a look at what you would need to level that is expensive.
lvl 7
Leaping/Bounding Boots 350-400k for the leaping boots. Bounding are free. Your theif will need these too. Get them.
Lvl 9
30k for Tonko: Ichi or quest it if you have the fame.
lvl 12
Traveler's Mantle 30k Not
neccesary, but it helps.
Utsusemi: Ichi 180k If you don't have this you shouldn't play this job. quest it if you have the fame.
lvl 14
Rings will cost you about 15-30k each depending on which ones you get.
lvl 15
All your elemental Ichis will cost around 25k at this level. you can buy them from a vendor, Chiyo (Norg).
Get some fresh Blood and go spawn Chocoboleech in Dangruff Wadi for a nice free level 15 R/EX Katana. It's good to hang onto for Level capped stuff.
If you want to do some Salvage, you can gather up some Hoshikazu gear and some of it will last you for a few levels. or
lvl 16
Bone +1 gear. 10k-15k per piece, 5 pieces total, but you would really only need 3 or 4 of em.
Lvl 19
Kurayami: Ichi for 30K. It's ninja blind. You want this. quest it if you have the fame.
lvl 21
You can upgrade your Bone+1 to Beetle +1. About the same price.
Night cape fo around 30k. Spike Necklace for 10k
lvl 23
Hojo: Ichi 50k. Ninja Slow. You want this. quest it if you have the fame.
lvl 24
You can upgrade to chain gear, but I wouldn't reccomend it. The 2 or 3 evasion you get from beetle will be better than the 10 or so extra def from the Chain stuff. Plus you get to add 10 more evasion at this level with an Emperor/Empress Hairpin. 700k for that. Also, trade your travelers Mantle for a Nomads Mantle (20k).
lvl 25
You could trade your beetle gear for shade +1. I didn't because it cost so much. About 100k-150k per piece. Kingdom Trousers are decent at 40k at this level. If you got the Hoshikazu at 15, you can do more salvage and upgrade it to Tsukikazu gear at this level.
lvl 29
Couple of Dodge Earrings, 30k each.
lvl 30
Rajas Ring gooooood. Finish CoP to get that one.
Jubaku:Ichi as well. 60k Ninja Paralyze. You want this. quest it if you have the fame.
lvl 33
Peacock Charm. 1.8 mill or an assload of camping. Good luck with that one.
lvl 34
Horomusha Kote or Ochimusha Kote(R/EX) or Ochiudo's Kote for 500k
lvl 35
You can upgrade that salavage gear again.
lvl 36
Ring upgrades, get what you want, but anythign decent is going to cost you 30k-50k each.
lvl 37
Utsusemi: Ni 350k. The reason you leveled ninja for a sub is mainly this spell.
And that's just the expensive stuff. There are lots of things under 10k for you to buy along the way as well. You'll also spend about 300k on tools to last the duration of leveling Ninja, for Blind, Para, Slow, and Shadows. That is of course, if you buy a stack of tool bags for all that, which you won't use half of by lvl 37. Only buy stacks of blind, para, slow tool bags if you want to level ninja to 75. Otherwise just buy them a stack at a time.
It can be done cheaper than all this without sucking too bad, but you don't wanna skimp on gear too much or you'll just die a lot. But it is expensive. I didn't even mention the Katanas.
Also, I played the job as a taru and only to 62. It got too expensive for me right about there. It's been a year or more since I leveled it so some of that stuff might be a bit out of date. Reguardless, people don't just say Nin is expensive to level. Ninja is expensive to level.