To find an 0603 resistor within 30% of 2 kiloohm:

./resistor 2k --tolerance 30

To find any capacitor within 10% of 1nF with a minimum voltage of 20V:

./capacitor 1nF --voltage 20 ./capacitor 1nF --voltage 20 --package ANY

Click the printed URL. Results are priced according to a quantity of 10 and sorted by ascending price, so you can probably use the first result.

The cheapest part number is printed.