You can expect to pay in the range of 50 to 200 EUR an hour, depending on the advisors skill and academic background. I doubt that it should take a financial consultant more than one or two hours to give you proper ideas whoon how to invest in ETFs.
From my point of view, you should rather check financial blogs like Mr. Money Mustache or - if you speak German - something like zendepot. The most important advices taken from these sites is:
- open a depot at OnVista, comdirect, ...
- set up a savings plan, which takes x EUR every month and puts that in a global ETF like MSCI World with a low annual cost of ~0.5%
- wait for the compound interest to kick in