Once activated the Mark of the Falling Tower requires a reagent to complete. Drop one of these onto the Master Ritual Stone. The cost is not on activation, the costs depends on what activator you will be using.
The Iron Block reagent will give low level ores, such as Lapis-lazuli, Iron and Redstone Ore. This will cost 1,000,000 LP to complete, the meteor radius will be 6 and will contain roughly 50% Ore
The Block of Gold reagent will give a bit of every Minecraft Vanilla Ores, but mainly Lapis-lazuli, Iron and Gold Ore. This will cost 2,500,000LP to complete, the meteor radius will be 7 and will contain around 80% Ore.
The Diamond Block reagent will give rarer ores, including Diamond Ore and Emerald Ore. This will cost 5,000,000LP to complete the meteor radius will be 4 and will contain 100% Ore.
Shortly after the ritual is completed, a meteor full of ore will be generated. This meteor causes a large explosion when generated. It is wise to keep this ritual several chunks away from base infrastructure. Its center will hit the highest block directly above the Master Ritual Stone and destroy any blocks in its way, including the ritual. A one block thick platform is sufficient to position the meteor. Moreover, if the highest block above the MRS is an Obsidian, it will prevent the explosion from destroying any block, but not from causing damage to nearby mobs and players. By using this method, all non-Air Blocks which would be stuck in the meteor will be kept intact, including the Obsidian. Placing it at least 10 blocks above the MRS will avoid any loss of the blocks provided by the meteor (if lower, it may merge with the structure of the Ritual).
On the left, a Diamond Tier meteor crashed into the Ritual. On the right, several meteors successively stopped using the Obsidian method, keeping the Ritual (and the Obsidian in the middle of the meteor) intact. The size of the meteor is determined by the reagent dropped on the Master Ritual Stone.
Check your Config folder for your mod pack to find out how much the activators cost and if there are different ones.