Everyone's needs are different and every location is different. Originally I wanted a few thousand acres, but had to settle for only a few hundred acres. But at least it's surrounded by hundreds of thousands of acres of National Forest lands. In this area it takes roughly 20 acres to feed one cow for about 7 months. We have good soil, in places, for gardening. We also have a short growing season. Usually our last snow is in late June, but we manage to grow a lot of stuff.
Land prices are very high right now, and I don't see them coming down in our lifetime. Especially in states where the government "owns" well over half of the land. In many areas in the mid west, south and east land and house prices are much less than out west. For most people it will take many years of constant saving to be able to afford even a small homestead. My original strategy was to buy a house and sell it every 5 years, then buy a house for double. Then I started buying land (timber land, ranch land). It worked out pretty well. In a few years we'll probably sell this place, or give it to the grandkids and start scaling down.