Thank you, Jason. Thanks to you I noticed, that products without version and size option didn't display any currency symbol at all. Your code fixed that.
Oddly though, for all other products the currency symbols still sticked right to the price. I found another line of code, that set the currency symbol and just added a space behind the € there.
document.getElementById('pricelabel').innerHTML=' € '+priceset;
Now everything works. Thanks!