A single John Deere tractor for a large farm is over $200,000 USED! Special equipment, like grain harvesters (combines) are MORE expensive.
A combine harvester can cost over $1,000,000 -- but then they can harvest a 20 feet wide swathe faster than walking speed. Heavy tractors not far behind a million. You get 4 large wheels that still gets traction on boggy ground.. It is hard to justify buying machinery like that if you have to borrow the money to do it.
There are various types of farming and agricultural machinery and equipment. The choice of a machine is determined by the type of work that needs to be accomplished. Tractors are widely used for farming and agriculture. In general, most types of tractor are able to mow, landscape, haul materials, and plough. This heavy piece of machinery varies widely in size, in the type of attachments that it can support, and the type of tasks that it is able to carry out. The more attachments the tractor supports, the more expensive the machinery tends to be.
They are but you will get your investment triplled if you have a lot of land to use them on.