Somebody knows about companies which provide domain reseller accounts without setup fee (only with payments for real registered domains and without conditions like hosting with them etc)?

http://www.webhostingtalk.com/forumdisplay.php?forumid=55

If you look through the Offers and Requests threads you will see all sorts of deals.

I suggest you go with experience and contact some of our WHT regulars (to the best of my knowledge, they all offer some sort of free eNom reseller account):

acts837 has www.NameZoom.net
Bashar offers enom reseller accounts (don't know the specific link - but you could PM him)
kohasi has www.895.org
zoli has www.DomainResell.biz


You also might checkout Directi.com. (But they are still having some growing pains lately from what I hear).