CiviEvent - Members Only Pricing
The easiest way to do this would be to use CiviDiscount.


Create a random code.
Place the discount amount - either as a monetary amount or percentage.
Add other settings to your desire.
Use drop down - discount for events - Select the event.
Use drop down Automatic discounts - use Automatic discount for existing members of type - chose the types.
Then under Automatic discount for Membership Statuses - choose the status - I would choose current and new - depending on your settings.
Choose price field options (under additional options) to choose the exact items you want discounted. Ignore this if all items are treated the same, such as 10% discount across the board. (thanks for reminder KilakwaBT)
Add any other settings to your desire.


If the member is logged in, all the discounts will be applied automatically if all of the conditions are met (no code needed).  As members tend to forget to login, you may want to write a note on the event page saying Members - Login for a special discount - or something to that extent.