I'm still trying to figure out if Tether is actually affecting the price

- Can you buy/sell bitcoin for tether?

- Has tether ever released an audit?

Yes you can, one of the bigger bitcoin US exchanges ONLY sells in tether. So if tether really did just print 1 billion fake dollars, that inflated the price of bitcoin substantially.

The had a CPA sign an affidavit swearing they had enough cash to match their tether tokens. The CPA firm seems legit. But he never looked at tether's books. The tether tokens are only one of many possible liabilities. If tether borrowed a bunch of money (from banks, users, etc), they could be easily insolvent while still having enough cash to only pay out tokens.

There is no legal mechanism to put tether token holders at the front of a bankruptcy creditor line.

And that was months ago. They printed 200 million tether yesterday. That amount seems unrealistically high.

Bittrex allows you to buy/sell tether.

https://www.coinhills.com/market/-usdt/bittrex/

You can buy and sell bitcoin for tether, but you can't exchange tether for dollars. I believe they claimed they had been audited but didn't release any information on it, unsure.