How do I reinstall OS X Lion from the recovery partition without the apple ID that purchased it?

Your MacPro1,1 originally shipped with Tiger or earlier OS installed. The seller erred in not erasing Lion and reinstalling its original OS prior to selling it to you. The effect of this is what you describe.

I really just want to get this computer back to it's out of the box state

To do that requires giving everything that was in the box to the new owner, most importantly its original OS X installation discs.

The correct way to transfer ownership of a Mac is to restore it to its original condition, using its originally supplied version of OS X on optical media. The seller should then supply those discs to the buyer. About 99% of eBay sellers fail to do this. Buyers understandably get upset when they encounter the situation you describe.

To answer your question, it is not possible to reinstall Lion from the Recovery partition without the Apple ID used to purchase it. Only its originally installed operating system can be transferred to subsequent owners - nothing purchased from the App Store can be transferred.

All this is addressed in Apple's end user licensing Agreement under Transfer. See 3A and B.

Let me know which corner and I'll grab it! However, if you want to restore it to factory built condition for purposes of selling or giving away your Pro, you absolutely need to obtain its original System Install DVD.

Contact Apple's Customer Support by phone on Monday. Provide your Mac Pro's serial number and explain you need its original discs. If you can get them to understand what you need, and if they are still available, it will only cost a nominal fee - $25 or so including shipping. Use the disc to erase its internal HD and reinstall its original OS. That is what the seller should have done for you, prior to selling it.

John is giving you the straight info...when Lion or Mountian Lion are installed by a user, only that user is licensed to have the OS. It should be removed before the computer is sold as a new owner can do nothing with updating. You can contact Apple for the original system disks, or try the on-line store or 1-800-MY-APPLE for a retail Mac OS X 10.6 set. From 10.6 you can on-line update to 10.6.8 and then to Lion or Mountain Lion.

Is there a way to install the OS without paying since Mavericks is now free? My default seems to be lion but is there a way to change it to Mavericks?

If you have Lion, and meet the system requirements found at http://www.apple.com/osx/specs you can download Mavericks from the Mac App Store.