This guide is no legal advice. Mojang decides what its EULA and usage guidelines mean and can change them at any time; what counts is always their current text on minecraft.net. If you are unsure about an item, ask a lawyer.
Two texts set the limits
The Minecraft End User License Agreement (EULA) and Mojang’s Minecraft Usage Guidelines say what you may do with Minecraft, also on a server that takes money. Both apply to every server, whichever store it uses.
Read them yourself before you plan your store; the links are below.
What a store may usually offer
Ranks with cosmetic perks, for example how a player’s name looks in chat.
Pets, particle trails and other cosmetic items that change how something looks, not how the game plays.
Supporter packages that help pay for the server, also at a price the buyer chooses.
What they have in common: a player who does not pay still plays the same game.
At SMPHUB: A SMPHUB store can sell all of these, once or for a period.
What is not allowed
Anything that gives paying players a gameplay advantage over others, for example stronger items, more resources or faster progress.
Capes, and anything made to look like a Minecraft cape.
Anything that suggests your server or store is made, approved or endorsed by Mojang or Microsoft.
At SMPHUB: Stores on SMPHUB that offer such items are suspended.
Ranks: the perks decide
A rank itself is fine; what it contains decides. A rank whose perks only change looks stays within the rules. A rank that unlocks a gameplay advantage, such as better gear or a command that speeds up progress, does not, whatever it is called.
So before you sell a rank, read its list of perks through the eyes of a player who does not pay.
A short check before you add a package
Does a player who does not pay miss anything that changes the game? Then leave it out.
Does anything look like a Minecraft cape? Then leave it out.
Does the description say plainly what the buyer gets? Buyers should know before they pay.
Are you unsure about an item? Leave it out until you have checked Mojang’s current text.
At SMPHUB: You can hide a package in your SMPHUB panel with one click while you check it.
How SMPHUB handles it
Every store on SMPHUB follows the same rules, set out in our terms for store owners. Stores sell only what the Minecraft EULA and Mojang’s usage guidelines allow; the terms also rule out offers that unlawfully disadvantage players or use prohibited gambling mechanisms.
At SMPHUB: SMPHUB is the seller in every store, and stores that break these rules are suspended. You decide what your store offers and stay responsible for it, as the terms for store owners say.