Need to get your sharp pencil and paper out. Start calculating your cost of production to the best of your ability. Start with all the known costs including but not limited to tractors, mower, rake, baler, oil, filters, grease, grease gun, knives, belts, hoses, fuel, twine/net, insurance, etc and add in your wage.
Do some research into gallons/hr fuel consumption of whatever tractor your looking at. Research your acre per hour for whatever mower and rake you want and estimate fuel usage, etc
When you get all of the known costs nailed down to a per hour, per acre, per bale basis add in a buffer for the unexpected costs (like the 1700 rear tire, or 7000 transmission rebuild, 5000 engine rebuild, etc). Add on top of that some saving for machine replacement down the road. When you are comfortable with all those costs you will know the actual cost to produce a bale, and you can set your prices accordingly and see if your customers are still there.