u/duck_of_the_heavens

I have been double bass for 3-4 years now and have rented a double bass from bassico during this time.
As a upper secondary student, I am looking for a bit of advice on buying my first instrument.
How reasonable is a price range of 2.5k to 3k euros for a 4/4 bass (what about other sizes) ?
Where is a good place to look (and maybe not to look),( I live in north east Germany) ?
I have watched a few videos with tips on what to look out for when buying a double bass but what are the most common mistakes ?
A bit of context:
I am relatively tall so I am looking for maybe a 4/4 bass.
I am also part of a school orchestra.
I try a mix of classical and jazz with German bow but also pizz.

Thanks allot!