The reason you have found conflicting information is that there are several ways to handle this and none of them is wrong. The key is to get the information on the return that matches that 1099-K and then back it out with a negative number so that none of it is taxed.
In the TurboTax software when you enter the 1099-K there will be several options for what the 1099-K is for. If you just tick the box marked 'personal item sales' then when you enter the amount from the 1099-K the system will ask you how much to exclude. Type the full amount and then it should be all over.
@tishamh