({2} magic symbol) ({G} magic symbol) ({W} magic symbol) plus enough mana to pay for commander tax, if applicable available.
Steps
Cast Farmer Cotton either from your hand or from the command zone by paying ({2} magic symbol) ({G} magic symbol) ({W} magic symbol) and commander tax, if applicable.
When Farmer Cotton enters the battlefield, it and Cloudstone Curio trigger.
Resolve the Cloudstone Curio trigger, choosing to return nothing to your hand from the battlefield.
Resolve the Farmer Cotton trigger, creating two 1/1 Halfling creature tokens and two Food, two Clue and two Treasure artifact tokens.
When the Halflings enter the battlefield, Cloudstone Curio triggers twice.
Resolve the first trigger, returning Farmer Cotton to your hand from the battlefield.
Resolve the second trigger, choosing to return nothing to your hand from the battlefield.
Activate the two Treasures by tapping and sacrificing them, adding ({G} magic symbol) ({W} magic symbol) .
Activate Ashnod's Altar by sacrificing a Halfling, adding ({C} magic symbol) ({C} magic symbol) .
Repeat.
Once you have infinite Halfling tokens, you may sacrifice them to get infinite colorless mana, which can be used to cast Farmer Cotton for an arbitrarily large amount of mana to create infinite Treasure tokens.