Ores and related materials are not available in the Item Shop on Skyblock. One way that users are able to get more Ore blocks to increase Island Level, is making and mining out a Cobblestone Generator. They are modified to give a custom palette of valuable blocks, instead of Cobblestone. As users increase their Island Level, they can obtain Generators that give them more valuable blocks, more frequently. Generators are also fully compatible with Minions, which means that the process of mining out a Generator can be automated. This is the suggested method of Generator Automation. Other methods which utilize things such as explosions or redstone, may have already been patched or nerfed to maintain reasonable server performance. There is also special types of Generators, such as Nether and End Generators. These Generators will produce blocks which are specific to these worlds. They can be unlocked by completing a series of quests, and reaching a specific Island Level.
/generator - Show a GUI with all Generators, and allows users to select any Generator for use that they currently have unlocked.
The following video shows how to make an extremely basic Cobblestone Generator. Any Cobblestone Generator tutorial found elsewhere should work on Cultivate, too.