Really glad we could help! The best way to get a true P and L view of your business is to enter all income and expenses. The Online Banking feature can really come in handy by reducing the amount of data entry needed, but it sounds like you have some other good systems in place to track your sales. I encourage you to do what works best for you!
You're right on the money (sorry for the lame pun) about invoices from vendors. They are expenses to your business. If you already paid for the expense at the time of sale, you'd enter it as an expense in QuickBooks (just like a customer-facing Sales Receipt). If you plan to pay for the invoice in the future, enter it as a bill and process it accordingly.
I hope the Getting Started Series we created for this particular community will come in handy down the road. We plan to continue building it out in the coming months. I want to leave you with a couple additional videos about the "Money out" workflow in QuickBooks and how to best record/track your expenses.
Best of luck to you, Joe. Lean on us whenever you need a hand.