What is better: Samson c03u,Samson c01u Pro or the Auna MIC-900 USB?

Solution
i would take a look at the audiotechnica atr2500usb and atr2020usb. the 2500 is about 75-80% the audio quality of the 2020 but with poorer built quality. its a good choice for a cheaper microphone though and likely better than the c03u or c01u pro. if you have the money i'd get a 2020usb / 2020usbplus though. or a 2020 (xlr) paired with a usb audio interface / mixer.
i would take a look at the audiotechnica atr2500usb and atr2020usb. the 2500 is about 75-80% the audio quality of the 2020 but with poorer built quality. its a good choice for a cheaper microphone though and likely better than the c03u or c01u pro. if you have the money i'd get a 2020usb / 2020usbplus though. or a 2020 (xlr) paired with a usb audio interface / mixer.
 
Solution

I got only 90 euros and I have to buy it froma amazon.de
 
international prices are quite a different animal. in the usa the samson and audiotechnicas are similar in cost (for the 2500 and c01u/c03u) but vastly different in germany.

this is why i suggested audiotechnica products https://www.youtube.com/watch?v=h2N-khMp2m8 though sadly international pricing in europe is much higher.

looking at the choices available to you on amazon de...

take a look at the samson meteor https://www.youtube.com/watch?v=bOoy-8ENCH4 which has good quality although the base is not good if you want to use it with a mic stand/arm.

it might just be me but i think the c01u pro sounds better than the c03u in comparison tests with other microphones https://www.youtube.com/watch?v=2Va4Cip3GfA but i'd suggest doing a bit of listening on your end as well. i do know that the samson mics do have a bit of self noise which could be a slight issue but for the price they arent a bad choice.