...you do realize how rare those Regalias and Stars are, right? And how unecessary they are for most of the game?
I have neither, and I have done just fine until I hit the Monochrome level difficulty missions (that is, S-rank, AA-rank, and Monochrome missions). Which is mostly remedied by good teams and summons.
Gold potions are good, but not worth anywhere near the worth of a Regalia or Star.
So, if you want something for it, stop bitching at those who are telling you that NO ONE with an ounce of sense will make that sort of trade, and find something else to trade it for. I am pretty much certain somone (*cough*Mechatrill*cough*) will be perfectly willing to trade one of the Wheel Super-Rares for it, and, I'm just guessing here, but I'm pretty sure you don't have all of those.
To be frank, you come off as a bit of a n00b...the bad kind, the kind that yells at people for not making bad trades in games.
Edit: As for not being able to do A-ranks...do you have Chakra Armor and/or the Headband? If you have both, and a Ninja Dog, you should be able to do A-ranks fine with Crazy Love Triangle...
Your best bet is to get yourself the Crazy Love Triangle team, then level Billy and Emosuke to level 3. Those two together, both at level 2 and level 3, will boost your range and strength amazingly.
Failing that, the Ro-Sham-Bo Redux team is also very good. If you really just plain CAN'T pass A-ranks, then maybe you need to work on getting better teams before you start jumping into A-rank missions.