@Panger, you have two separate situations here:
Purchasing
I’ll deal with purchasing first. Manager’s tax processes are set up on the assumption that most taxes will be offsetting, such as VAT. In other words, you will collect taxes from customers, pay taxes to suppliers, and remit the balance to the tax authority. Because of your special small business status, you cannot offset taxes paid against taxes collected. Therefore, do not use any tax codes on your purchases. You have two options:
A. Include the tax paid within the unit price of every line item on a purchase invoice or payment form. For you, tax paid on purchases means simply a higher price. If you purchase inventory items this way, the tax will be included in their cost in the Inventory on hand account. In other words, you will be capitalizing the tax as a temporary asset, then later passing it through as the cost of goods sold to become an expense. This might not be permissible under German tax regulations. You should consult a qualified accountant or the tax authority about this. I am not saying there is anything morally or ethically questionable about this option. But some jurisdictions permit you to capitalize the full acquisition cost of inventory, including such things as tax, shipping, etc., and some jurisdictions do not. Just do your research and follow the rules.
B. Separate the tax paid on its own line item, posted to an expense account created for the purpose. This gives you visibility about where you are spending your money. It does not capitalize taxes as part of inventory (if that is even an issue for you). Again, consult qualified sources to determine whether this expense is deductible for such purposes as figuring income tax. (Financial and tax accounting are seldom the same. But the tax is a real expense and reduces your net profit.)
Whichever option you choose, the tax ultimately becomes an expense on your profit and loss statement. This is why tax authorities have different regulations about capitalizing taxes on inventory. Some are satisfied with the expense being recognized when goods are sold. Others want the expense recognized in the period when payment is made.
From your perspective, Option B is easier, because you do not need to prorate taxes paid to unit prices. And you get the benefit of the expense immediately. Since you are generating internal forms (purchase invoices and payments), you need not worry how they will be interpreted by outsiders.
Selling
Selling is a little more complex, because you need to show customers something recognizable and understandable on sales invoices and receipts. So for sales, you do want to use tax codes. Fortunately, Manager has a solution, called flat rate tax. Read the Guide: Create and use tax codes | Manager. The section on flat rate schemes is about 3/4 of the way through the Guide.
In your case, you will have to create a tax liability account, even though you will actually not remit anything to the government. Otherwise, the program will not work. Just follow the instructions in the Guide. Also create a custom, single rate tax code for 10.7%. Give it a name like Agricultural tax 10.7%. Check the box for Flat rate, and in the Flat rate field, enter 0%.
Your customer (using your example numbers) will see an invoice for the amount €2000, plus €221,40 tax, for a total of €2221,40. To them, this will seem perfectly routine. But your tax liability account will show no change. Instead, the income account to which you post the €2000 amount for the goods will increase by €2221,40.
The tax authority will get back some of the money it let you keep by not remitting VAT by taxing this extra income. Depending on your marginal income tax rate and the ratio of your sales to purchases, you might actually pay more than the 10.7% they would have received through VAT. (That is something else to discuss with an accountant. It could be—if you have a choice—that participating in this program is not worth it.)
