I put an item into the auction house without knowing how much it went for & then after completing it saw the average selling price was 25k more than my starting price. Can I take it out? If not is there a page I can go to so I know going prices for items?

Hello and welcome to forums!
Unfortunately, there's no way to withdraw your items from auction house once you've set them for bids. For future prevention of this problem, if you are trying to find out a price, you can set your item out for 3 hours and unrealistic amount of coins (eg. 900 million) and then simply check its average sale price. After 3 hours time, you can set it out again for desired and realistic amount of coins. Other way to check prices is to post "Pricechecks" with names and possibly pictures in "Trading" section of forums, there are few players who know a lot when it comes to pricing items and they will help you for sure.

THANK YOU so very much!

Welcome, have a good day