Hello
What would be the best online place to buy variety of bolts,nuts,spacers in EU ? to be used in different DIY projects
Here for screws and nuts. Spacers are difficult to source in small amounts, id recommend reichelt.de
Thanks @fcd72 ; do you think any of the Home Improvements chains in Germany ( OBI , Hornbach etc. ) carry spacers on ?
negative.
Hornbauch… Mhmmm… I generally find it difficult to find places that stock Hex standoffs in the EU… End up ordering round ones from China in stead… 
If the German hardware stores are in any way like the Danish ones(and they probably are), they won’t carry anything as small as a M3 or the like, but rather have everything you could possible want, if you were making 10HE+ modules, or massive shruthi-sandwiches…
das musikding.de is a nice german online shop where you can order bolts, nuts and spacers in small amounts. And shipping cost is only 2,50€ for <250g.
I tend to search for them on ebay. Usually find a few.