The big question is: what kind of a cleric are you?
If you're focused on offensive spellcasting and healing in that order:
Periapt of Wisdom +2 (4,000)
Lesser rod of extend spell (3000--great for summon moster, swift march, mass conviction, spiritual weapon, magic circle vs. evil, and later on good for magic vestment)
Pearl of Power 1 x4 (4000)
+1 vest of resistance (1000--though it wouldn't hurt too much to get a cloak)
(If allowed) least augment crystals of energy resistance for your armor and buckler (500 ea)
Some healing or spell augmenting items from the MIC--which I don't have handy right now. Armbands of Maximize Healing, Sash of the Healer, or even armbands of elusive action (a nice way to avoid an AoO).
Buff and bash
+2 periapt of wisdom (4000)
+1 vest of resistance (1000)
+1 armor (1000)
+1 weapon and a weapon augment crystal of energy assault--or just buy a +1 frost/flaming/shock weapon if that isn't available (8300)
scrolls
Healing and buffing
+2 periapt of wisdom (4000)
+2 vest of resistance (4000)
lesser rod of extend spell (3000)
pearl of power 1 x3 (1000x3)
least armor augment crystal of energy resistance (500)
Only for the buff and bash cleric do I actually recommend magic armor. One point of AC difference probably isn't as important as another pearl of power 1 unless you are on the front lines by intention.
I highly recommend the armor and weapon augment crystals. In fact, I think they're generally broken and wouldn't allow them in my games. So, if your DM does, take them.
Although it involved smuggling illegal herbal goods to the Dwarven kingdom, My 5th level Cleric with no magic items is in a metropolis where anything and everything can be purchased.
So what should I buy being that I posses no magic weapons or armor of any sort or potions scrolls etc...
what is the biggest bang for my buck to maximize my purchases in these areas..
utility
defense
offense