I’ve been looking at green houses. Don’t know much about them, but here’s a link for starters.
My friend has the first greenhouse shown in your link. She loves it, but she’s not a prepper, she’s a hobby gardener. IMO these are rather pricey, good for starting seedlings but way too small to grow hothouse veggies in winter, if that’s what you’re looking for.
A less expensive alternative is rectangular raised beds, constructed with 2x4s. Then in winter you can put hoop houses over them. You just use several flexible PVC pipes, bent into dome shapes, stabilized with 3 straight PVC attached horizontally, one on each side and at top. Then cover with greenhouse plastic, and you’ve got a hothouse for winter growing.
The raised beds mean I don’t need to bend as much for ground crops.
One negative: raised beds need to be hand watered with a hose; can’t lay a soaker hose.
Also, what I do, is leave the hoops on year round, but cover in spring with bird netting. Keeps the bunnies and birds from eating all my food.
To keep from feeling guilty, I plant a few extra goodies round about, especially for the little critters.