I'm interested in trying to play as a Summoner, but at 20 hours in I have found zero items so far that allow me to summon minions. What is the earliest/easiest summoner weapon to get? I've looked at the Wiki but am having a hard time telling. Is it the Slime Staff from the Slime King? Thanks!
The Finch Staff is the easiest summoner weapon to get in Journey Mode, because you start with it.
In other game modes it depends what you mean by "easy". Abigail's Flower only requires that you die, replace the tombstone, and wait. But you might be waiting a while.
The easiest one that doesn't rely on luck is the Hornet Staff. Kill the Queen Bee and you're guaranteed enough Bee Wax to craft it.