I personally never use One-Time Vendor. I have not tested in a few years but it used to show in the journal entries as One-Time Vendor instead of the real company name. Also, in your case, you are referring to consumables, hence you will be rebuying them again. Do you change vendors each time you buy them or do you always go back to Staples for example? I would post these to an account like Office Supplies that you would normally find in the 5000-5999 range in your chart of accounts.
Sounds like you are still in history mode eg. this is the first year you have been using Simply. If your business was running before using Simply you would have some closing balances from another bookkeeping system as of the cut-off date that you stopped using the other system. These are the numbers you use to start using Simply. This would included the invoice from last year.
However, as of the cut-off date, you would probably still owe money to vendors and your customers may still owe you money. So under each vendor ledger there would be a Historical Transactions tab and you can enter the individual invoices still owing as of the cut-off date. If invoices were paid before the cut-off date, ignore them for Simply because they would be in the opening balance numbers you entered in the Chart of Accounts ledgers (Company Module).
So how do you enter the current purchase of ink? Click on the Payables module, click on Purchases. Enter the vendor name (if the name is not already in the list, then you can do a Full Add to add the address information, Quick Add to add just the name to the list to track the amounts not paid or Continue if it was a cash/cheque/credit/debit transaction. Continue does not add the vendor to the list (and therefore you will not be able to track the purchases from that vendor). You can enter a description if you like, the date of the invoice, the dollars, the tax code and the account (Office Supplies as mentioned above), etc. Post.
