Good day, peterMD!
I'm glad you're getting help with tracking your cigarette purchases and sales in the QuickBooks Community. I'm happy to assist you.
First, I'd like to go over recording your client's prepayment since this is a bit of a process. Basically, the road map is to track them into a liability account first and then turn them into customer credits to pay the cigarettes. You'll find all the detailed set of steps in this article: Record a retainer or deposit.
About purchasing the items. If you purchased cigarettes based on demand, you can make those transactions billable so you can add them to your patients' invoices. Then, use the credits to pay the invoice, which is also discussed in the Retainer article. However, I believe you're a pass-through entity and might be concerned about the taxation. Having said that, I would recommend consulting an accounting professional to get advice about the pass-through account first. Then, you can get back to us if they have specific instructions that you find challenging to do in QuickBooks.
We're just right here to continue helping you with this. Take care and have a good one!