Help me create a magical item

[MensurB]

Hi, we might be starting a new epic level campaign, and I was wondering if I can create a magical item that gives me a plus of at least 20 to my spellcraft skill (I have the create wonderous item feat). I talked to my DM and he said that that would be fine becasue of the high spellcraft DC's on epic spells, however, he want's me to research it and I looked into the DMG and it just sounded/looked too complicated. Can anybody help me out? What kind of bonus can I create at twentieth level, higher or lover than a +20?
Thank you for your help.

 

[kreynolds]

31 and higher is an epic-level bonus. 30 and below is not. You can easily handle a 30 with a caster level of 20.

 

[MensurB]

Thank you, but what exactly do I need to create that item, gold and exp??

 

[kreynolds]

The skill bonus cost formula is bonus squared x 20gp. So, +30 to Spellcraft would be 18,000gp (30 x 30 x 20gp). You would spend half that in gold pieces for materials (9,000gp) and 1/25th that in XP (720XP) to make the item.