Stormsplitter and Phyrexian Altar on the battlefield.
({9} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) at most, depending on how many Stormsplitters you control available.
Steps
Csat Wurmcalling with buyback by paying ({3} magic symbol) ({G} magic symbol) ({G} magic symbol) .
Each Stormsplitter you control triggers, creating that many token copies of Stormsplitter.
Resolve Wurmcalling, creating a 1/1 Wurm creature token and returning Wurmcalling to your hand.
Activate Phyrexian Altar by sacrificing the Wurm, adding ({G} magic symbol) .
If you control at least 8 Stormsplitters, activate Phyrexian Altar four times by sacrificing four Stormsplitter tokens, adding ({3} magic symbol) ({G} magic symbol) .