1. I'd get the 85 SA. I haven't checked recently, but I'm pretty sure you can buy the materials from the Crafting (or maybe Legendary) vendor at the Skirmish Camp. You buy them with medallions and skirmish marks, so no need to spend gold.
Originally Posted by kutsuu
Also, personally, I wouldn't bother with getting a 75 SA unless you already have all the mats or level slowly. If you're fast at leveling, there's no point in spending resources on a weapon you'll throw away in a week or two. But, if you think it'll take you several months, then a 75 SA might make more sense.
2. Skirmish marks come quickly enough if you get into raids and other group content. Personally, I wouldn't run skirms for the sole purpose of acquiring marks, although the XP is pretty good.
Regarding teals, I generally would not buy from the AH. At least on Crickhollow, you can sometimes see people giving away some teals for free on glff. Join a kin if you're not already in one - oftentimes, kinmates give stuff to each other for free.
The crafted jewelry and Grand River items are actually pretty good. The latter involves some grinding, but is worth the effort.
Finally, when you get to 84, start rebuilding Hytbold. That's great XP and also gets you a very good suit of armor.