umm well theres a lot.depends on trust too.if youre trusted you can get it from .40-55 if youre buying bulk. for you id say .70-.75 depends on how much you order.
Pretty much trusted members here cost more to buy RSGP off them because well.. they are trusted, and you will get your gold with or without the use of a OMM, which brings me to the point, if you go thro a highly trusted member you wont need to use a OMM. [Trusted = Voiu, Plznate,RsProd,Punker,KingTjin ect.]
If you do cheap out and go for the cheaper RSGP/$ rate and also ditch the trusted member an trade without the OMM, you might think your saving cash .. till the trades over and their MSN goes from online to , offline and your left with nothing.
I've gathered so far if i'm to buy GP i'd probably be buying it from a trusted member of Sythe for atleast $0.75/m. (estimated?) - now if i'm selling the GP i'd probably be selling it @ $0.75/m aswell.. I've also gathered if i'm to sell GP to a buyer/seller than they'd pay $0.60-65/m.