"Todas las marcas y modelos."

[twymer]

In what situations do we use "todo"/"toda" instead of "todos"/"todas"?

[enoksrd]

Spanish adjectives change to match the gender and number of the noun they modify: http://www.studyspanish.com/lessons/adj1.htm

So, here we use the feminine plural "todas" because the noun "marcas" itself is feminine and plural.

[Naypam]

What are "brands" in this sentence?

I feel like I'm missing something from magazine pop-culture but perhaps not! "marcas" were "marks" I thought, but apparently not in this context.

[Luis]

"Marcas" can also mean "brands" as in: "Coca Cola es una buena marca".