You do not typically "buy" an individual badge from a store like a standard clothing item; instead, you request them from creators or other collectors.
To display more than the standard set of badges, users can purchase a Badge Canvas for $5 at the IMVU Store. Acquiring Badges from Other Users buy badges imvu
Collecting is a major social pillar in IMVU. Many users take pride in filling their profile grids with rare or aesthetically pleasing "blings". Because creators can revoke badges at any time, maintaining good social standing within the community is essential for high-end collectors. You do not typically "buy" an individual badge