In both the desktop and web application, the standard workflow loads the last price at which an item was received as soon as that item is added to a receipt.
This price can always be changed, of course. However, it can be used until the actual price is known — and the actual price will likely differ from the current price by less than a zero price would.
This workflow is also available via the API by using the "previousValue" parameter with an empty value "" on the price list object. See the example below for details.
<winstrom>
<skladovy-pohyb>
<typDokl>code:STANDARD</typDokl>
<typPohybuK>typPohybu.prijem</typPohybuK>
<kod>12345</kod>
<sklad>code:PLZEŇ</sklad>
<skladovePolozky>
<skladovy-pohyb-polozka>
<cenik previousValue="">code:XK 654501</cenik>
<sklad>code:PLZEŇ</sklad>
</skladovy-pohyb-polozka>
</skladovePolozky>
</skladovy-pohyb>
</winstrom>