You've probably read how you can make your own foldable v-flats, but finding high-quality foam can be difficult and you're lazy, so you're never going to get around to it anyway. Luckily, you can buy them prebuilt and have them shipped right to your door.
V-FLAT WORLD recently sent us two of their foldable v-flats, and I was excited to test them out. The v-flats we have been using were made from ultra-cheap foam purchased from Lowe's for about $40 a piece. We had to paint them ourselves with black and white paint, and they are constantly shedding foam all over our studio.
I was impressed with foam quality from V-FLAT WORLD. It's not officially "Gatorfoam," which is the highest quality of foam core, but it is a similar build. The foam is one inch thick and is coated with a matte black and white shell on opposite sides, which is perfect for photo and video. The hinges are made with standard gaffers tape and the seam is connected with velcro. Even though it's built with DIY materials, it's much nicer than I would have been able to do on my own. The Velcro portion of the v-flat does have a small opening that may or may not pose a problem with light spill depending on how you use them. The v-flat also comes with a carrying bag so that you can easily bring it on location.
The one downside I can see with this v-flat is that it is only 80 inches tall rather than the standard 96 inches of most v-flats. I'm 6 feet tall, and it was still plenty tall for me, but for some scenarios, you may prefer the extra height.
V-FLAT WORLD sells one of these for $195 and two for $379. I was honestly pretty shocked at these prices until I started looking into the cost of building these myself. If you buy cheap foam core at Lowe's or Michael's, you're certainly going to save a ton of money, but they will fall apart quickly. If you want to build a similar quality v-flat, you may actually spend more than $200.
1/2 inch Gatorfoam costs over $100 per 96-inch piece and you'll have to buy in bulk. You may have trouble finding Gatorfoam that is black on one side and white on the other. If you can find the perfect piece of foam, you have a studio, and you don't need to travel with your v-flats, I would probably suggest building them yourself, because you will be able to build a bigger v-flat with the highest quality foam without any light leak in the middle. But, if you want something that you can fold up and put away or take on location with you, V-FLAT WORLD is a great option (actually, it's your only option) if you don't want to deal with making them yourself.