Plugins are the weapons in STARSEED and long-term it’s more important to get and level them up rather than characters. The amount of combat power and extra skills they give is just too good to ignore.
As a free to play player, you get plenty of currency to pull here (including 1 guaranteed multi per week in Asnia City). I would recommend saving some of these pulls for new characters, just in case. When it comes to the gacha for plugins:
4% base rate for plugins but instead of getting them directly, you obtain shards. 10 shards at 72%, 20 shards at 23%, 50 shards at 4% and 100 shards at 1%.
You can wishlist 5 plugins and each one of them will get a 15% chance of appearing. The first time you get a plugin, it will drop 50 shards so you get the base copy.