How can I put a pricetag on a painting?

Lovely Steemians,

I have this painting that I've made a few months ago. I want to sell it but I have no idea how much I should ask for it.
Well asked some friend of mine some said €600,- and others €40,- .
I am not a artist or anything. I just love to create...if it's nailart, food, paintings etc etc.
This painting I want to sell so I can help my friend who lives in St Martin to get here.

It took me 2 days to make it.
It's 60 cm wide and 80 cm long.
Painted all with acrylic.

So.....do you have any suggestions??
Thank you....