Words for amounts are followed by the partitive:

• paljon — a lot of, lots of: paljon kalaa — lots of fish
• vähän — a little: vähän maitoa — a little milk
• kilo, litra, pussi — a kilo, a litre, a bag: kilo perunoita — a kilo of potatoes

There's one new twist. Things you count — berries, potatoes, apples — go into the plural partitive, ending in -ja / -jä or -ita / -itä:

Singular	Plural partitive	English
marja	marjoja	berries
mustikka	mustikoita	blueberries
mansikka	mansikoita	strawberries
peruna	perunoita	potatoes
omena	omenoita	apples

Things you can't count — fish as food, milk, coffee — keep the singular partitive: kalaa, maitoa, kahvia. For now, learn the market words as you see them; the plural comes back later in the course.