Acheter à vil prix = To buy dirt cheap, for a mere song.
Acheter chat en poche = To buy a pig in a poke.
Acheter par francs et vendre par écus = To buy in the cheapest market and sell in the dearest; To sell at a high profit.
Achever
C’est un voleur achevé = He is an arrant thief.
Achoppement
La pierre d’achoppement = The stumbling-block.
Acquérir
*Le bien mal acquis ne profite jamais = Ill-gotten gains benefit no one; Cheats never prosper; Ill got, ill spent.