my first commercial license sale on 500px

I just made my first commercial license sale on 500px.  This is only the second time, ever, that someone licensed my photography
(outside of contract work where I’ve done product photography as part of product catalog projects).  The first sale I made was this photo of the Weezer concert at Adobe MAX.  I don’t even attempt to comprehend the details of all the differences in the plethora of licensing agreements, from free to various forms of paid licensing.  As a user / customer, I generally buy my stock images through Dreamstime and iStock, because they are cheap.  But my first sale, on Dreamstime, made me a whopping forty-two cents.  In contrast, I was pleasantly surprised to find that my commercial license on 500px goes for $250, of which I actually get to keep 70% of the sale.  I still have no illusions about making money off photography sales, any more than I have of racing in the Tour de France.  My interest in photography is similar to my interest in cycling – I do it because I enjoy it.  Once it becomes work, it tends to suck the pleasure out of it.  Still, today’s sale was a nice surprise.  I did have to edit the image slightly to crop out a little bit of face that was showing, but the 500px staff was quite pleasant to deal with and they accepted my submission readily.  Actually, it was nice to actually have some direct correspondence with them, as opposed to Dreamstime where I believe there are human beings reviewing the submissions, but the sheer volume of their throughput must prevent them from such personal interactions.