If its a big one a relatively inexpensively bought flat belt drive lathe can make large, occasional, jobs worthwhile.
A decent condition, modern gear head lathe in large sizes will be pretty expensive and a cheap one worn in enough places to be a right PIA.
If you have space an old, bought'n paid for, machine tucked away at the back can easily earn its keep on one a month or so work whether directly or by adding the capability to do the whole contract where a job includes some big parts. Onsey twosey or repair work on large parts can be hard for customers to arrange. The big shops with modern machines need to charge high to cover depreciation and need to keep the work flowing to keep utilisation up. = expensive and hafta wait your turn. Guy with a big ole lathe at the back of the shop can basically just charge time. Good chance of being able to fit it in quickly too.
The "Joe got me sorted" thing is, up to a point, good for reputation and advertising. Just don't charge too cheap or folk will take you for a soft touch and bring you all the crap. Turning away rubbish jobs without damaging your reputation is an art form.
Clive