Asking the price: Wie viel kostet das?
The price question:
- Wie viel kostet der Rock?
- or simply Was kostet das Brot?
Both are correct. The answer recycles your Unit 2 numbers: Das kostet fünf Euro neunzig.
kosten behaves like a normal verb: das Brot kostet, die Eier kosten.
Tip
Wie viel kostet …? and Was kostet …? mean the same — pick one and say it with confidence.