If you have a year 2 better devil's you can infuse it with a stronger year 2 better devil's for glimmer only But if you choose to infuse it with any other primary weapon, it'll cost you glimmer, shards, cores, and planetary materials (you can infuse it with any primary: shot gun sniper auto rifle etc) If you need cores, glimmer, shards, or planetary materials you can buy directly from the spider- but it's not cheap, he rotates planetary materials and some times he takes glimmer some times it's shards