how much would a boot cost for a 1990 ford mustang convertible? i'll check later on
and i got red interior and black trim if that helps any?

68949, Most of the trim parts for the 1990 are discontinued, as is the convertible boot, we cannot order them anymore, sorry.

what color would the boot be? do they go by the trim color or the interior color?

The boot came in Black, Blue, White, Titanium, or Scarlet (red) I don't know what the original color of the boot on your car would be.