Welcome!
Do find a local Model Engineering Society, and join. You will meet a lot of fellow enthusiasts and expertise, face to face. many will be happy to give face to face, and hands on demonstration if you have an immediate problem, as well as pleasant social contact (One happy day, not too far away, we hope )
As already said, what you want to make / repair will have a great influence on which lathe you need.
As examples, you can't skim brake discs on a mini lathe, but you would not want to make parts for a watch on a machine capable of swinging something 18" in diameter.
Equally, if you want to refurbish the tele forks on your motorcycle, you will need a lathe with a large bore in the Headstock, and a reasonable centre distance.
A worn old lathe may let you make the odd nut and bolt, but may cause you problems if you want to make a 1.5 cc engine for a model aircraft.
If you want make O gauge locomotives, a mini lathe would probably suit, but not if your ambition is to produce a half scale Traction Engine..
One person can just about manage moving a mini lathe, but anything larger will need at least two people, especially if the machine is unbalanced by a hefty motor hanging off the back.
Also where do you plan to have your workshop?
Hauling a 300Kg lathe up two flights of stairs, or down into a cellar will not be much fun. (Not impossible, but there are easier things to do )
Nor will your neighbours be impressed if you make a lot of noise, just when someone is trying to sleep, or watch TV.
If you fancy a second hand lathe, do take someone knowledgeable with you to see it, try the machine and check that all the accessories are there and in reasonable condition.
Just a few thoughts!
Howard