A villager summoner. Make sure you're using it in a commandblock, otherwise it will not work. To get a command block, type in chat /give @p minecraft:command_block. To do the command, copy/paste the command in and power the commandblock. The villager will trade you MineBoots. Also, the villager's trade is cheap, so it is a good command for a starter kit. Copy/paste the command in, and power it for your armor trader!