Many of the spam posts are scams and account hijackers.
And people asking for rep spam are questionable too.

And will that save me money on transaction fees for small purchases?

Spam Spam Spam Spam Spam Spam Spam Spam Spam Spam This group looks a bit dead

I've said it before but it's worth repeating, Kinguin would rock if I could import my steam wishlist to it and then show prices next to the games, perhaps with a steam store price comparison.

SCAM,
they will take your money, they will take your item(s) and you will get nothing back.

'Free Skins' and free $50 spam posts are scams, ban these people, delete their posts, report them to valve via their profile.