[Darryl Ramm]

Pro Tools 9, 10 or 11 can still be sold via an iLok asset transfer, you don't need to physically purchase on an iLok. If buying an "unregistered" version of Pro Tools software you need to make sure it comes with all the registration paperwork and it should have a blank iLok with it as well. Be careful of scammers that sell a worthless DVD-ROM (actually worth $15 or so -- Avid sells them as backup DVD-ROMs) containing software with no electronic license transfer or no license on a physical iLok.

I would be careful with Pro Tools 9 because it lacks the latest OS support, even Pro Tools 10 and 10 Express have not been updated much recently and lack official support for the latest OSes.

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And if you want to go that route buy from somebody with a good selling history who hopefully won't rip you off.

Buying used can be a good option if you know what you are doing and are careful.

There is no guarantee that you'll be able to use that licenses to upgrade in future (even if past similar upgrades have been OK) and no guarantee that you'll be able to download future updates. e.g. New Pro Tools 11 updates are only pushed to user's Avid accounts, a move likely done to discourage used license sales and to help thwart license cracking.