The schema.org define two schemas interesting for our use case, https://schema.org/Person and https://schema.org/BuyAction. The BuyAction schema will be use to store a specific expense (see for example form G103 3.1 "auditory and oral messages").
This schema contains 4 properties that we are going to use to store the expenses linked to the form:
- price
- priceCurrency
- description
- identifier