Most/all lvl. 70s SHOULD qualify for a 5-piece, almost free rare (blue) PvP set, 2 sets, or 3 sets (important for hybrids).
Here is how to get yours:
1) be HONORED with any of these factions: Honor Hold, Cenerion Expediition, Sha'tar, Lower City, and/or the Caverns of Time
2) for each of these faction you are honored with, go to their Quartermaster. If you don't know where, look on wikipedia, Thott, or ask in guild or general chat in game. The FASTEST way to CoT quartermaster is to take the free portal from the High Elf girl in World's End Tavern in Lower City Shattrath (I would suggest doing that one last, and then HS back if you are not a mage)
3) your new, blue, PvP piece(s) will be on the LAST page of each quartermaster items. As a Druid, there were 3 sets available to me - the Kodohide, Dragonhide, and Wyrmhide. But Raessa had only 1 set (as a mage). Also see if you have any other cool stuff availble while there! The cheapest piece was the gloves, for 9g. I think head was most expensive, and it costed less than 20g. ***There is NO honor or BG marks or Arena points to get these - just small gold!!!***
4) you will get set bonuses for 2 piece (+35 to Resilience), and a 4-piece bonus (depends upon the class & set). You do NOT need to wear all 5!
5) you will want to enhance those pieces - for the gem sockets, go with uncommon (green) gems from AH - should cost 1-5g each (check our bank first!!!). The order of importance is this:
*+hit
*+dam
*+crit
*+your main stats
6) for shoulder enhance, use your Scryer/Aldor turnins in your Aldor/Scryer bank. For pants, an armor kit from an LW, or special thread from a tailor. For head, a quartermaster Glyph is usually best, but they cost around 85g - so maybe just a +10 stam armor kit (from leatherworking) would be ok. ALL the head pieces use a meta gem - you may have Spirit Shard in your bank from Auch instances - 8 of those will buy you a soulbound meta-gem from the Z~~~ (Zhand???) mage guy in Allerian Stronghold, SE of Shatt. For chest, I almost always say +6 stats is best. For gloves, just get a good enchant for your class.
Total, you can get a 5 piece rare-class PvP set and all your simple gem (not including meta) for under 100g. Guildies can help you with other stuffs. And lots of time, the pieces + their set bonus may be better than what you have now. For hybrids (druid, pally, shaman), this is a GREAT way to get a 2nd or 3rd set of gear for your backup roles.
I hope this help!
~D~