I have been trying to use an anvil to combine my iron pick silktouack and other enchant ments to heal the iron pick. It tells me to pay 27 How do I do that
You need 27 levels to repair it. I suggest looking up "Anvils" on minecraft wiki http://www.minecraftwiki.net/wiki/Anvil
It means that it requires you to have 27 levels of experience. On the bottom of your screen, there may be some green numbers, it needs to be at least 27 for you to be able to repair it. You can gain experience from killing mobs, mining, breeding mobs, or smelting ores or food.