How do I enter the following option trade: I sold Put options on XYZ stock, and I collected $1 on the sale. The Put options expired worthless, so I pocketed the $1.

[teddy_lu]

Turbotax lets me enter the cost basis, but there is no option for me to input the proceeds.  My cost is zero and my proceeds should be $1.

[GeorgeM777]

Enter the short put as you described in your post.  That is, your sales proceeds are $1, and your cost is zero.  Chronologically it may seem odd because your opening transaction was a sale (Sell to Open) and rather than buying the option back (Buy to Close) you chose to let it expire.  Thus, enter your cost basis as zero, and if you have to enter a purchase date, use the date you shorted the option.  Your sale date would then be the date the option expired worthless and enter the $1 as sale proceeds.  

@teddy_lu