This is turning into one of those home improvement shows where they completely renovate a house for "$1000"...but that price only includes the cost of things like wood, drapes, end tables and shrubbery and does not include the countless hours of labor by professional landscapers, interior decorators, and construction crews that would EASILY send the total cost of the project in the tens-of-thousands of dollars.
The OP might end up with a really nice bike thanks to the help of the good people here. Otherwise that $100 bike might end up costing a fortune to fix up.