Aicha Mrabet,
you can follow below process for Free item catagory which is not releavent for price:
Business Data:
Completion Rule = blank
Billing Relevance = blank
Billing Plan Type = blank
Billing Block = blank
Pricing = blank
Statistical value = blank
Revenue Recognition = blank
Delimit. Start Date = blank
Transaction flow :
Incompletion procedure = 24
PartnerDetermProced. = N [ Standard Item]
thanks
Md. Enayet Hossain