One detail is enough.
A form asks for a category, merchant and note when all you remember is the amount. The small expense goes unrecorded while you decide.
LemonBook lets an incomplete record exist. Choose Money Out or Money In and save one meaningful detail. The rest can wait until you have it.

How it works
Capture the useful part
Save the amount or a short name while it is still easy to remember.
Use Siri when your hands are busy
Ask Siri to capture an expense in LemonBook. File the captured amount from the Siri Inbox when you next open the app.
Organize when you are ready
Search the ledger, add categories and fill in missing details. Entries without amounts cannot contribute to a money total.
A closer look
A small free book
Free includes one Book, unlimited entries and categories, search and filters, Siri capture and iCloud sync.
Grow only when you need to
Plus adds multiple Books, attachments and CSV/PDF export through a one-time purchase.

A few details
Must an entry have an amount?
No. Another meaningful detail can be enough. A completely empty entry is refused.
Can I use it on both iPhone and iPad?
Yes. LemonBook supports both, with entries syncing through your own iCloud account.
Does Free expire?
The current App Store listing describes Free as an ongoing version, not a trial. Plus unlocks additional features.