Hi, you must be new here.
Well for Ace 4*, it depends on which card.
But for a bad 4*, its probably around 2 stat stones (iii), while the good ones like Ace Golem may reach up to 14 stat stones (iii).

5* Aces? You seriously want to know?
At least 100 stat stones (iii).

Wow.. u quite keng wor.. started playing GC for 10 days,
u have enuf strenght to win till A+ in Novice..
U have help from friends?

Congrats! Just 10 days and score 2 5* and did well in coli. Wish i had your kinda luck. Hope you continue to do well.

Sorry to hear that, bro. But I think GC doesn't care whether your iTunes is different or from whatever country it comes from. I downloaded my GC on iPad mini using a new Japan ID which I later changed to US store. Then, I bought coins in that GC account using my old US itunes. Then last week, I changed to another Malaysian ID and bought coins using my debit card. OF course I had to re-install GC everytime I do these purchases. My point is, GC doesn't care what Id you're using. I even can buy coins on my Jap GC using my US ID, but due to having credit balance, I couldn't do that.

So despite these failed attempts, I can safely narrow down your problem to your iTunes account, not GC. You could try these test if you're willing:
1) try buy IAP from other games. This is to narrow down the problem is not because of IAP.
2) try transfer your GCsave data to another iOS device and buy from there. This would require a virgin iOS device without GC. Perhaps if your friends have any iPod touch lying around.

If anything, you could probably request Apple to refund the gift card due to you unable to purchase iap using it. Don't be too sad bro, at least your credit is still there. Its just probably Steve Jobs dunwan you to spend it on games instead.
That's because mbr is showing off what he already got in his stash. Except for that ace Morrigan. I'd be damned if he already have that as well.
you buying or selling?
Best answer, it depends on the guardian actually.
Ace Jotunn is kinda worthless despite it being ace while Fast Vampire could probably worth more than that Ace Jotun. I remember I bought my Ace Qiong Ji for 35 SS from NightHeart, but that was months ago and he gave me a cheap price. Today rate, an Ace Qiong Ji could probably fetch 75 - 100 SS.

An ace vamp wont do u good if u want to reach top 200

You need Fast Sphinx Empress!! 

I got:
Ace Jormungandr
Fast Hecatoncheir
Fast Medusa
Chaotic Taowu

All max level. I'll let you have 'em for 55 SS each. Hows that? 

I have 15-20 max 4* as feeders
I guess they should be worth 2-3 stat(iii) each. Saves GP especially after spending 5k GP on rebirth

Stat stone (iii) is worth 20 - 25 SS now. So your 30 SS and one Wis(iii) should just be just nice. Whoch one do you prefer? Since you havent share your deck, hard for me to recommend any. Fast Heca is good and solid for a strong finisher, but Taowu is a decent tanker with Last Stand skill. Jorm is a good tanker, but slow. Nedusa is elemental giardian, so good against physical guardians, but I guess se's just so-so.

Due to Crimson Keep, price of (III) has dropped a lot.
1(III) is about 22-25SS for non-MP, 15-18SS for MP(iii)

Why don't you buy Ace Jormungandr from funnytone? 30ss+1WIS(III) should be more than enough for what he's asking.

I actually have an Ace Hecatoncheir, but its still at level 22. I'll let you have him for the same price of my fast Heca if you're interested.

Wow urs should be a 5* deck isn't it to be at rank 200?

U got jorm already so ace hec would be good (if u hv the time and resource to lvl up) else go for max hec'
My opinion

I dont know which one is your offer. Ace baha is yours?
i don't like Pazuzu despite him being a fast guardian. Ramiel is also one of the weakest elemental guardian. Try to find Brigid to replace him. Jotunn....ughh, dunno why I despise this card so much, sorry. For me, these three should be replaced ASAP.
Not to rush you, but I'll be offline soon. Make your decision or later when I'm back home around 2pm onwards okay? Its a no brainer actually, Ace Heca is the best of the lot. He is Narasimha's younger brother and Vampire's stepbrother and Golem's classmate. 

A level 55 4* feeder gives the same EXP as eating 15 SS.
You need around 69 SS or 4.5x max level 4* guardian to fully level up a 5* from level 1 to level 60.