mage armor, +4 AC, 1st level spell slot
shield, +4 AC, 1st level spell slot
Dodge feat, +1 AC, feat slot
1,000 gp Bracers of Armor +1 AC
1,015 gp Mithral Buckler +1 AC
1,000 gp upgrade mithral buckler +1 enhancement bonus
2,000 gp Ring of Protection +1 AC
2,000 gp Amulet of Natural Armor +1 AC
3,000 gp upgrade bucker to +2
3,000 gp upgrade bracers to +2
4,000 gp Gloves of Dexterity +1 AC
5,000 gp dusty rose Ioun stone +1 AC
5,000 gp upgrade buckler to +3
5,000 gp upgrade bracers to +3
6,000 gp upgrade ring to +2
6,000 gp upgrade amulet to +2
7,000 gp upgrade buckler to +4
7,000 gp upgrade bracers to +4
9,000 gp upgrade buckler to +5
9,000 gp upgrade bracers to +5
10,000 gp upgrade ring to +3
10,000 gp upgrade amulet to +3
10,000 gp upgrade gloves to +4 DEX (+2 AC)
11,000 gp upgrade bracers to +6
12,000 gp boots of speed
13,000 gp monk's belt
13,000 gp upgrade bracers to +7
14,000 gp upgrade ring to +4
14,000 gp upgrade amulet to +4
15,000 gp upgrade bracers to +8
18,000 gp upgrade ring to +5
18,000 gp upgrade amulet to +5
20,000 gp upgrade gloves to +6 (+3 AC)
...and that is the path of fastest AC improvement for your money over the career of your character. That's 30 points of AC from items.