You are asking the wrong question. It really doesn't cost anything to title your dog except the trial fee ($40-$85 depending on the club) and the cost of a scorebook.
What you are asking is what is the cost of access? Access to a helper, to equipment, to knowledge. This will vary widely depending on numerous factors.
As far as whether the dog will be more successful being sent to a trainer or trained by yourself, that largely depends on the who the trainer is and what your skills are.