This isn’t quite surburban, but I know of some cheap international options.
I used to live in Sierra Leone, a country in West Africa. Land out in the middle of nowhere can be as little as $300 for around half an acre, but you have to own it jointly with a local that you trust. You can get land for a little more up in the 3000 foot mountains surrounding the capital and port city, Freetown. Once I have had a good career I plan on buying land up the mountain from the city and building a small concrete fortress with large storage reserves and maybe a fruit tree. It may not be as easy for others, but I know the language and culture so it would work. I’d of course have a helipad for easy access.
I really think it depends with your plan and what you intend to with the land. If you want to keep livestock, you’ll definitely need more land, perhaps more than an acre. I love that you can still do some bit of gardening on your piece of land.