Let me tackle some of your questions, and give some ideas/opinions about raising your pigeon.
white homing pigeon for sale for $100.00. I bought it the next day haha.
That is a going price from a retailer who sells for a profit, and does pay for pricey shipping. I purchased my white homers for under $20 each, but did have to get them myself. The HIGH DOLLAR pigeons, are usually racing line winner bloodlines.
My plan is to keep him as a personal pet but also keep him to fly from a mile or 5 miles away from his coop. I've only has him for one day and i know i cant let him fly until he has been locked up for a month or 2.
My pigeons were pets as well. I would loft fly them daily. I did toss fly some, and they did return. I flew those that were homeset to my loft. Keeping your pigeon locked up for 2 months is no guarantee that he will homeset to your loft. Being a lone pigeon is also a factor, that once freed after 2 months, may decide to split and search out a mate. You will be out one pigeon, and $100 cash
I am only feeding him one ounce of food a day, i do this so one he doesnt get fat and two he comes back to be fed (a part of training). Should i give it unlimited water? I know you shouldn't give them unlimited food but what about water?
I never tried to put my pigeons on a diet. They had food available inside loft. They never got fat.

. I know many keepers do feed their pigeons twice per day. If you choose that route, then have feed available for 30 minutes, and remove any after that period. I do know that certain pro pigeon peeps do adhere to a scientific diet for their racers. I never raced, and had no desires to do so. My pigeons were my pets.
Provide plenty of water always, and make sure it is deep enough for pigeon to stick whole beak into. They do not drink like chickens. Also provide a tub of water for him to bathe in. 2 to 3 inches deep is fine.
Also i will not be getting him a mate i understand it makes it harder for him to want to return but im going to spend time with it alot. That is your personal choice, but take into consideration, that pigeons are gregarious and would like some companionship of a mate. If you do decide to just keep one, then I suggest you do not release to free-fly. May decide not to return.
Ask anything else you would like to know, and join a large group of pigeon fanciers on this active thread. Much information there just from reading.
https://www.backyardchickens.com/threads/pigeon-talk.1276029/page-934WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,