I would buy a perm mount with gold rather than risk all those crowns. Perm mounts and good pets are rare in card packs. You are much better off farming for pets and hatching. Packs are better used for trying for desired gear. Just my opinion.
I can't stress enough that the packs are chance based. You could open twice as many packs and not get what you want, which is why the rare, and ultra rare rewards are so nice.
It is a risk.
personally I would get a permanent mount from the crown store as a sure thing. Later, when I had some extra money to spend, I would try for a mount from a pack as a cosmetic upgrade. If I were unlucky and opened no mounts, at least I would still have ol' reliable to carry me from place to place.
Do consider saving up for the gift card bundles, many of the older ones are sold on this site. They often provide matching sets. One bundle offers a sultan's palace home with, Persian themed armor, a snake charmer's flute (wand) with it's own battle animations , and a magic carpet mount. It is more expensive, but all the items are guaranteed, and their quality is every bit as good as the stuff found in the random packs. The bundles that don't have houses are usually cheaper, just make sure you read the description of each one so you know which one has the stuff you want.
Well I did a little bit of my own research, and the packs I am suggestions are based purely off of the amount of permanent mounts and pets available in each.
Perreau's Plentiful Pet Provisions - Not only does it have 26 available pets, the pets aren't all rare drops. However, this pack has no mounts in it.
Nightmare Pack - Yes, I know the pack isn't available for another month or so, but it has 20, all around decent, pets, not to mention its 9 permanent mounts.
Kirin's Hoard Pack - This pack has 15 pets, and 3 available permanent mounts.
Hoard of the Hydra - The pack itself contains 15 pets as well, but 1 permanent mount.
Skyvern's Hoard - 13 pets, and 1 permanent mount.
Raven's Hoard - 12 pets, 2 permanent mounts.
Pharaoh's Hoard - 11 pets, 2 permanent mounts.
Phoenix Hoard - 9 pets, 1 permanent mount.
Wyvern's Hoard - 6 pets, but 8 permanent mounts.
All in all, I think it depends on the risk you want to take. The majority (if not all) of the mounts are epic drops, meaning extremely rare to get. The pets tend to be uncommon, rare, or ultra-rare. A permanent mount from the crown shop for gold or crowns is a guaranteed to give you what you want, but if you wanna take the risk, I suggest this: Google "wizard101 ______ (Hoard pack name)"
Look through the ones you want, and see what the pets and mounts are that you want.
If you end up buying the packs, just know that you most likely won't get what you want, and prepare to have to have to settle with some junk and a different pet, or temporary mount.
Just a heads up, the Wyvern mounts, the phoenix, the skyvern, the hydra, and the golden throne mount from the pharaoh's hoard are all epic drops. I do believe both raven mounts and the kirin's are also epic drops.
If you're set on wanting a pet, the plentiful pet provisions one has the most pets that drop consistently, you would have a better chance there.
Once again, it's a game of chance. And also, some of these pets and mounts you can farm or buy in the shop.