Did you set up the code wrong? That often happens. Also, you need to input the (M) code first.
If the max money code still doesn't work, use these:
All Ammunition (Press Select)
AH68-9Q55-W1WZZ
YT79-C2U2-FP2HZ
HMTH-FKUQ-H3U6H
MK2U-RMGC-XWDZP
6N5D-JP1W-VKUWF
88J4-A6BP-8GYJE
J1CQ-31KK-CVDH1
03AH-5PBC-9K2T7
All Armor (Press Select)
15DA-65R3-H2Q76
YT79-C2U2-FP2HZ
76JT-7NA8-UJ7C2
2AW1-P1DB-3ZCPU
58Z1-2EWX-MVF48
A57H-VTND-G00N3
J84F-TZVK-CY7AA
03AH-5PBC-9K2T7
All Accessories (Press Select)
TARH-ZX7D-TZPUY
YT79-C2U2-FP2HZ
KXYP-NDTJ-XPYTT
TZ4M-NX65-6613N
F3MX-RR1P-ADTB2
QXX5-U29E-V2N97
V1PB-1BDT-JUQYJ
03AH-5PBC-9K2T7
All Weapons (Press Select)
AXP3-TW44-C3A3N
YT79-C2U2-FP2HZ
BHT0-M5T2-7MK1G
PAQR-6E93-QWRKM
0ZJW-QPMT-H1YVG
EKKC-B5G0-EYD7F
9ZWW-20XR-4G9NE
9R8Z-7HET-QTY30
94DC-H943-NTF2C
YKHX-T3U3-U1MP5
03AH-5PBC-9K2T7
Other than all this, you need to make sure your code corresponds to your game's nation
(eg: Test1)Game: America, Code: Europe, Result: may not work...
Test2)Game: America, Code: America, Result: Works!)
If you game is European version, try this;
L1+L2 For Max Gils
UNWR-YV16-PQRQ7
C7VQ-HYJ6-UH5ZP
04EB-FUTP-NU9AA
Hope I helped...