Exclusive cosmetics can only be obtained via a special method, this can include events, giveaways, a special promotion, or most commonly by opening chests.

An exclusive skin can be buyable for a short time, however this is usually because they’re tied to an event that is taking place, for an example during the Merrymaker Event, the exclusive skin Merrymaker Lian was buyable without opening chests, however since the event is over, the skin is no longer directly buyable.

Examples of Exclusive Skins and how to get them

Merrymaker Lian - Orignally tied to the Merrymaker Event, but now can only be obtained via Chests

Omega Dredge - While currently buyable as of the making of this guide, the skin will no longer be directly buyable when the event is over

Resplendent Jenos - Can be obtained for free buy linking your Facebook account with your HiRez account, there is no other way to get this skin.
https://my.hirezstudios.com/linked-accounts

Oni Talus - Can only be unboxed via chests, as of right now, the only chest he's in is the Feudal Chest

Limited Cosmetics when they're first introduced work similar to exclusive skins, where they need a special method to unlock, however after the special method is gone, they will no longer be obtainable by any usual means.

Examples of Limited Skins

Soul Eater Jenos - Purchased all Siege of Ascension Peak bundles before the event ended

Mixer Khan - Obtain 600 Mixer Points by watching the official Paladins channel on Mixer, while your accounts are linked before the start of Season 3.

Twitch Prime King - Claim the Twitch Prime King bundle on Twitch Prime, while your accounts are linked before the set date.

Volcanic Makoa - Reach level 30 in the original Paladins PC Closed/Open Beta

HOWEVER!

Some limited skins are still available during certain events, HiRez/Mojo distribute codes that are for Limited skins during a special Charity Event in the Spring called the Spring Fling that's hosted ever year.

BUT! The skins are usually very expensive due to the following...

A. Your donating for charity, not for the skins
B. They want to keep the skins decently rare for old owners

Here's an example from 2018's Spring Fling
https://smitescrub.com/2018/05/15/hi-rez-studios-4th-annual-spring-fling-announced/

So don't go in the event with £2/$2/€2 expecting a Limited Skin, get £100/$100/€100+ if you want to get one, just remember it's for charity.

Unlimited skins are skins that were the final reward of a previous event for buying everything, these skins can still be bought, however the cost of the skin is the total amount of what each of the skins/cosmetics costed during the event.

For an example you want an Unlimited skin, and it was part of an event with 4 special cosmetics, and each of them costed 500 crystals, 500 x 4 = 2000, meaning to get the unlimited skin, you'll need 2000 Crystals to get it, if you buy an Unlimited Skin outside it's event, you will NOT get any other skins that were part of the event, ONLY the Unlimited Skin.

Examples of Unlimited Skins

Fullmoon Viktor - Costs 1500 Crystals

Merrymaker Maeve - Costs 1200 Crystals

Hopefully with this guide, you understand what each tag means, so you don't end up mixing them up, and potentially missing out on a skin you enjoy.