Let’s see.  Off the top of my head, I can think of two variants for Hulk costumes.  There is the classic Hulk comic book costume (green and purple pants).  And there is the 2008 movie costume (darker or olive green with more pronounced muscles and not necessarily purple pants).  Everything else seem to stem from these two color schemes in sizes (i.e. adult Hulk costume, child Hulk costume, kids Hulk costume, Hulk toddler costume, baby Hulk costume, childrens Hulk costume, infant Hulk costume, etc.) and/or style (i.e. inflatable Hulk costume, Hulk costume shirt, Hulk game costumes, Ultimate Alliance Hulk costumes, Hulk muscle costume).

When you search for “Hulk costume” on Amazon or other online shopping sites, you get the varying results as listed above.  And they’re actually pretty cool looking.

Adult Hulk Costume

Inflatable Hulk costume for Adult 2008 Movie

Hulk muscle costume for adult (deluxe and movie styles)

Standard Adult Hulk Costume Green & Purple Pants

Adult Hulk Super Deluxe Costumes 2008 Movie and Classic Comic Book
These are the expensive ones. Perfect for conventions, festivals, and, of course, Halloween parties!

Baby Hulk Costume

Baby Hulk Costume
Cute little Hulky costume. Perfect for your baby, infant, or toddler.

Kids Hulk Costume

Inflatable Hulk Costume Child Size

Kids Muscle Hulk Costume

Incredible Hulk Movie Costume Child Size

Deluxe Hulk Kids Costumes