As far as straight out buying, cultural is one of the best ways to go. However, there are other armors to get also.
First though, Slot 7 augs are general augs, and there are many to find. The slot 12 however is generally only made from raid drop items and no trade. There are of course some augs that will fit in a 12, but it is designed for chronal, discordant, baze, and last blood augs primarly, such as
Last Blood of the Healer. DoN merchants offer some augs that will fit in slot 12 also, but they in no way compare to augs such as these. If you want to look up some of the others, they start with names such as "Chronal Seal of", "Discordant Seal of", and "Bazu Seal of". If you want to search the DoN merchants check out
EQ Utilities.
A few other possibilities when you reach 70 or 71, include, the TSS quested armor, which for shaman is
Spirit-Seared Chain Coat if you get a power source, other wise it's just
Seared Chain Coat which is the same without effects, i.e. just AC, stats, HP/Mana/End, and resists. Powersources are fairly easy to come by however.
Another option is the TBS armor, which for 70 level Shaman would be
Citizen's Energeiac Chain Coat and the 75 level Shaman one would be
Praetorian's Energeiac Chain Coat. TBS is similar to DoN armor, in that you have to build up enough faction, and also enough of the specific coin to buy the items.
The PoR armor is also good.
I can't remember any better at 67 that are groupable that are better than cultural, but there may be. The TSS and TBS armors are definitely the way to go when you get high enough level to get them for upgrades that don't require any raiding.
Yther Ore.