Things like tires, spokes, wheels. Ideally good quality, but this is also for my shitty city bike. Durability over speed
I have used bike24.com and bike-discount.com, both German online stores. Neither of them have solely European stuff, though
These are a little bit high end 😂. My bike is a €35 granny pulled out of the canal.
If your budget is that low, then the only place is local second hand shops.
You can find some cheaper stuff there too, just select size and sort from lowest price
I mean, you could just order from decathlon? If you’re fishing bikes out of canals, you probably even have a brick and mortar decathlon near you.
Perhaps at Rose Bikes the parts you’re searching for are cheaper.
For older bikes there is dutchbikebits.com
It’s not that expensive, decathlon is cheaper but you can find there parts for old POS bikes with good price.
Could always go to your local bike shop and ask them if they have some things lying around? Mine used to give me some tools he didn’t need anymore and always had some spare parts that were still perfect