I have a small Hobby Greenhouse and I bought these trays for starting seeds. They are very affordable and have been durable enough for me to use for the past three years. I start a lot of seeds and these give me 32 starts in a small space.
They are made of strong plastic. They can be torn, but I haven't had much trouble with that happening. They are easy to fill with the seed starting mix and when the plants are ready to be transplanted the plastic is pliable enough to squeeze so I can easily pop the plug out. They are sturdy enough for me to carry them without using a flat, but if I need to use a flat they fit perfectly. They have good drainage holes, so I never have to worry about my baby seedlings getting water logged.
If you want to save a lot of money on plants, these are a great saver!