This behaviour occurs if an article you created yourself has not been assigned a price in any price list, or the article has not been assigned the correct tax rate.
To set a price and tax rate, do the following:
1. Click on Master data.
2. Click Articles.
3. Click on Search.
4. Find your article.
5. Click on Edit.
6. Enter a price in the desired price list.
7. Select the correct tax rate.
8. Click Save.
"0.00" is also a valid price.
If you are not sure which price list the price should be entered in, simply enter a price in all lists.