I would like to know if there are sites able to print CDs at an economic price in Europe to produce a demo in an economic way.

not sure if it's good for Europe but maybe go take a look at Kunaki.com and easydisc.com

everyone wants "economic" ways... what kind of quantity are you talking about?

About 200-300

we used http://www.cdprintmasta.com/ to do a 100-run of a digipak CD once and we were very happy...

look for pressing plants in your country, too, they might have competitive prices and the obvious advantages of locality and language...

if it's your first pressing, get someone to help you. each plant has its own quirks and there are several "usual" pitfalls...

last but not least, once you've settled on an offer, and before you commit, have a look in case another pressing plant gives you 500 copies for example for the exact same money... you can use the "bonus" CDs for promos, etc.

best of luck!

I've used Kunaki for black-tray jewel cases with one-sided inserts. They're rates are very affordable for any sized run and they also do plain CDs as well as CD jackets.

https://kunaki.com/