You've got a few choices. You can do a search on Amazon for "bird carrier." They tend to be a bit pricey but are built specifically for birds.
Alternatively, you can go buy a small animal carrier or the smallest cat carrier you can find. Ideally it should be a hard carrier so you can seat-belt it into the car. Buy a rope perch, or any kind of perch that you can force the ends through the sides. The goal is a sturdy container with a solid perch for the bird to grasp. I've had the best luck with the rope perches. Place some paper towels or newspaper on the floor of the carrier and you're set!
Cover the carrier with a blanket or towel. The bird will sleep for the car ride as long as it's dark.
To move the bird into the carrier, do it tail first. Have the bird sitting on one of your hands and then pet its neck with the other hand while backing it into the carrier. Place it on the perch, remove your hands, and close the carrier. If you back the bird in, there's less chance of panic or attempts to escape.
If you can, slowly introduce the carrier to the bird by placing good food and treats in the carrier and letting the bird go in and out of it as much as it wants for a period of time - at least a couple weeks.
I've transported several small birds this way. I did have one carrier that I had to modify with some plexiglass because the bird could fit her head through the bars but not get out. Keep an eye out for that. Most birds never cared to try, but I had one that tried to escape that way. In an emergency, bolt cutters do go through the wire very easily.