Question about Creality Ender 3 V2

Of course, this depends on the material and the print settings (e.g. infill density, etc.). In addition, how many test prints you make for a new part and in between a part is not usable due to a printing error...

A general statement can hardly be made. I mostly print with cheap PLA ordered from Digitec. The roll costs me between 30-50 Sfr. A single print of a teacup would cost something in the centime range... I consider the cost of the material to be a "cost of use". Similar to soap... I don't think about the cost of washing my hands, I buy new soap in between and it lasts for a while...