The official Deep Glow plugin is paid software.

Repeat a third time with an even larger radius for a "deep" volumetric feel. Quick Chromatic Aberration (Free Plugin):

: Red Giant offers powerful glow tools; while they are subscription-based, their free trials are a great way to complete a single project. Why Investing in the Official Version is Worth It

Presets use built-in After Effects tools but are pre-configured to mimic the high-end look of Deep Glow:

While not a 1:1 clone of Deep Glow, there are several free utility plugins and scripts that improve the default glow:

Built for speed, outperforming many internal AE effects.