My Stamps...

Today I forgot the kitchen and garden, and worked a long while with my Finnish stamp collection. I tried to figure out the average value of it. There are stamps from 1890 to 1950 something... If only I good understand what W1 and W 2 mean. And so many other things of what all depends..
I would like to sell it but how not to get cheated...
This is not all I have, I have an old book of countries that does not exist any more. My problem is not to know the real value.. But I love to work with them and look at them.many are so beautiful, especially pieces presenting paintings..