Open Helm

An Open Helm is the first Helm-class headwear available throughout the Golden Sun series. It is generally the first Helm-class gear available to the player.

Basic Description by Game
An Open Helm increases the wearer's base Defense by 9 points. As a common item, it can be bought repeatedly from vendors for 180 coins each and sold for 135 coins each.

It is sold in armor vendors at Bilibin and Imil in Golden Sun, at Alhafra and Garoh in Golden Sun: The Lost Age, and at Harapa in Golden Sun: Dark Dawn. This helm can be equipped on all warrior-style Adepts in both games, namely Isaac and Garet in the first game, together with Felix and Piers in the second, followed by Matthew, Tyrell, and Eoleo in the third.

Analysis
In Golden Sun, the Open Helm is a pretty good upgrade to the Leather Caps that Isaac and Garet are probably wearing, and is worth your generally low amounts of funds you would most likely have at that point. From a financial perspective, they are much better than the Wooden Cap, which costs twice as much yet only gives one more point to Defense.

In The Lost Age, an Open Helm could be considered for Felix once the party reaches Alhafra, but be advised that in the town Mikasalla, which can be entered even before Alhafra, the far stronger Bronze Helm is sold for 600 coins, so it is very likely a much better idea to shop there.

In Dark Dawn, the Open Helm is a likely upgrade from any Leather Caps Matthew and Tyrell may have. Given that the player will not have access to stronger headwear until reaching Kaocho at the least, Open Helms are an excellent choice. Should the player buy Open Helms, they can pass over the Wooden Caps in Kaocho, which would only be incrementally stronger, for the Bronze Helms in Ayuthay.