I would make a list of ALL the things you want to be able to do now, and in several years. Remember as you complete tasks, new projects will be possible. This will help narrow down what will work now and in the future- as well as help decide if buying bigger now or in the future is the best way to go.
As you work on the list, remember to include the implements you will need to go along with the tractor. this is where the list can grow fairly big. Research as you go- learn about what different implements do and do-not do.
Once you get your "list" together, start looking around on different manufacturers web sites- see what each offers for their models. if you are able to, drive around the dealers lot and look at what is there ( I still do this...bugs my wife:thumbsup
Print out specs for several brands and models, along with your list- start visiting dealers. There is another thread that goes into what TBN'rs like to see in dealerships and sales people. There are also several very good dealers on this site that chime in once in a while (Barlows, Meesicks, Sweet Tractors to name a few).
Ask for a dealer to compare and contrast with other brands, ask specific questions. Be prepared to walk away DO NOT BUY ON YOUR FIRST VISIT!!! Do not answer if asked anything like " how much are you planning on spending" or "what payment are you looking for". Those are the evil tactics of the finance world. You may be able to afford a small payment..and they will see that you pay forever

Although your budget is very important, do your research first. you may have to adjust your list of "want vs need" once you start seeing prices.
There is tons of information on this site- I have spent many hours reading and researching here. Had I known about TBN years ago, I would have done a lot of things different.
Good luck and have fun on your quest!
