I have recently bought an old farm with 4acres of land.
Tractor will be used mainly to mow grass but also for other general work
Will be looking at second hand market and have limited budget.
Another post requests more info - that would be very helpful. The tractor size and capabilities is directly related to how long a project will take. You mentioned mowing so lets go there.
A tractor with a 60 inch mower traveling at 3.5 mph can mow 4 acres in 2 hours. Assume that this will not hold true on the first couple of mowings for various reasons, but later when you are accustomed to the tractor and have the high grass under control this will apply. Consult the following site to size your tractor and mower to fit the time you want to spend mowing. A Craftsman will take over 4 hours if it will even make the first pass.
TractorData.com - Mowing with tractors
Consider a front end loader. Think of a FEL as 4 guys that can lift 200 lbs each at your beck and call. If you are a senior like I am you will quickly appreciate the abilities of an FEL. Four guys cannot move as much dirt as quickly as I can with my FEL.
Consider NEW for this reason. I recently acquired a
B3200 (18K) on my signature. No money down, 0% interest for 60 months and $300 per month. The tractor has a warranty and I can buy an extended warranty anytime before the 1st year is up. My 5 year old
B7510 has never failed to start.
If you have limited time to work on the farm my suggestion is buy a little larger than what you really think you need and buy something reliable. You don't want to spend half your time repairing before you can get to work. If you are a mechanic you may be ok with that. I prefer to get work done.
If you are going to farm, garden, clear land or go into a building project there are several implements that can help you do those jobs.
List your projects for more detailed advice.