If you are lucky, you can get these starting at 1,20€ apiece on AliExpress.
Edit: yes, currently available for 1,29€ in the bundle sale ("Free shipping for three or more items"). Whenever possible, try to get the ones without pre-soldered header pins and solder them yourself. Soldered pins bend very easily during shipping.
Edit: yes, currently available for 1,29€ in the bundle sale ("Free shipping for three or more items"). Whenever possible, try to get the ones without pre-soldered header pins and solder them yourself. Soldered pins bend very easily during shipping.