It's random. There are many many rewards.
On average (ish) .... Rolling 100 times would give you I think 4 rolls in the right range. Even when in the right range there is only a small chance of getting a horse, perhaps 1 in 10 something like that?
So something like 250 rolls @ 15 shards a time should have a reasonable-ish chance so about 3750 shards. You've spent 500 so you are about 13% of the way there.
But here's the thing, it's random, so it might happen on your very next roll. Or After spending 10K shards you might still not have it.
if you want a white/black horse, I would buy the collectors edition of FeyWild which has white/black unicorns, that's pretty close enough. That a much cheaper and guaranteed way of getting something very close to what you want.
Rolling to get something on the rare tables is suckers bet all the way, doesn't matter if you are VIP or premium or free.
Yeah and if u buy Feywild Collector's Edition for the White Unicorn u will also get:
a Tome of Destiny +1 (Historic) for Actually it's 1-per-Server (Not all characters) on All servers (including Future HardCore) each such tomes is worth 3,495DDOpts
plus a Character Slot
plus the heroic Feymuse
plus Shifter species/race (but perhaps u already got that)
(plus some cosmetics)
if u buy Ultimate for the Black Unicorn u will also get (in addition to White Unicorn):
Tome of Destiny +1 (Feywild) for ALL Characters on All servers (including Future HardCore) each such tomes is worth 3,495DDOpts that's on top of the Destiny Tome+1(Historic) above
(I just checked when I created a new Razorclaw shifter on HardCore 9 I got both the Tomes (the Historic is 1-per-Server actually, but each HC server u can get it and transfer back)
plus the Epic Feymuse
plus Razorcloaw species/race
plus pets
plus the stuff in above Collector's Edition
teleporter
cosmetics
etc.
Most Importantly is u will Definitely get the above instead of RNG causing doubt and stress and-or FUD
