[3.5] Magic Item GP Cost: Am I Missing Something?

[Sstoopidtallkid]

What about warlocks they can use any magic item because of the Use magic item skill so how does the restriction apply to them

Everyone can Use Magic Device to overcome the restriction, though Warlocks are better at it than anyone else. Generally by 4th level a Warlock can pretend to be a Class, by 7th a Race, and by 9th an alignment, assumiong basic amounts of investment. Other classes are somewhat different due to the lack of an auto-10 mechanic, so they wouldn't be able to use the items until much later.