How should I enter a sales report that lists my items sold (tax included), removes a sales commission total, and is accompanied by a check for the balance?

“and they withhold their commission amount (10%) from the sales”

Let’s restate this: They keep money from Payments, and this is Not going to Affect your Sales Data. This is part of Banking. This is in lieu of you getting all the funds, and then you paying them their commission.

“which occurred in each pay period. Here is an example of what the sales report looks like:”

You need them to be a Vendor Name. The Vendor data is Never part of the Customer transaction.

“I want to be able to account for the commission amount withheld as an expense. The only way I know to record an expense without a bill is to “write a check” from petty cash or one of the bank accounts.”

Like this:

Create a Bank account for Barter.

Create the sales for the Full Prices. “Deposit” this to the Barter Bank.

Use Write Check for the Vendor Name, for the Commission.

“This would only work if I was actually receiving the full $50 in one of those accounts.”

You are confusing PAYMENT with SALES. Yes, you have $50 Sales = Gross Income.

“Do I make a fictitious account “depositing” and then “paying” the commission out of that fictitious account?”

It is called Barter. It is instead of you and them trading Checks.

“As for the sales tax, the store does not add tax onto the sale price, but I am required to pay 8.025% to the state and I would like to utilize QB to tell me how much tax I owe. In reading other q&a regarding this issue, I thought I understood that the US version of QB Pro 2016 does not do price inclusive of tax.”

You set your prices however you want to. Set up the Sales as all Income, and then pay taxes as All Expense. There is no sales tax function to use in QB for this activity; turn off that function entirely.

I attached a little Excel worksheet for back-calculating sales taxes from Sales Gross.

Here is how to Summarize Sales:

http://longforsuccess.com/daily-sales-summary-for-retailers-restaurants-ecommerce-and-more/