How many letters does the top answer for “a pocket-size case for holding papers and paper money” have?

The most common answer is billfold (8 letters).

Crossword clue: a pocket-size case for holding papers and paper money

3 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

billfold 8 letters wn-def

a pocket-size case for holding papers and paper money

notecase 8 letters wn-def

a pocket-size case for holding papers and paper money

wallet 6 letters wn-def

a pocket-size case for holding papers and paper money