When making magical items the price is very important, how do i determine the creation price of an item? is there a magical formula? lol
There is a formula, under the creating magic items section in the core rule book.
However, as has been noted, it's often as much an art as it is a science. I use that formula as a rough guide, and then try to match it up with other items to see if they feel right. Think about what level you want to have the item come into play and look at the wealth by level charts. Is the price of your item something you think a character of whatever level would actually pay? What's it's value compared with some other common items, such as a cloak of resistance.