Photostock plus was the first site I join but I didn't know it isn't free. Actually, as I understood, you have to pay some 50$ per year to upload pictures there (maybe the amount isn't correct, but I know it wasn't some big money). So, I decided not to do that because I found free agencies...
But, photostock plus is sending me emails all the time, almost every few days I get some mail from them. Does anyone have experience with them? How is it possible that they are in business when there are so many free agencies and some of them are really huge. I mean, I know there is a place for everyone in this market, but again... They have so aggressive marketing campaign like they are best in this business....

Of course I don't think so. Plus, I didn't pay them, and I don't plan to do it. I didn't upload images there, as I said.
I just have to notice that it's probably a company much smaller than some big companies around. But they still have enough money to have very aggressive campaign. Maybe these big companies around us could really give more money to promote them selves, or at least to pay us little more...

Oh, let them go.... no time to discuss about them... Sometimes I start really boring topic

Another one like this in the UK is Fotolibra.

They say 'membership is free'. But your free membership entitles you to place the grand total of 12 images with them.   

Anything more and you have to pay.

Take a look at what they have on offer. I'd guess that very few who pay see any sort of return on their money.

I can't understand why anyone should want to join them ... unless it's because they can't get their images accepted anywhere else.