required beforehand: a prerequisite fund of knowledge. something prerequisite: A visa is still a prerequisite for travel in many countries.
This can get a little pricey -- an iPhone 6 screen repair kit costs about $150 -- but it is cheaper than buying a new phone altogether. Of course, not all of us have the skills or time to fix our own phone screens.
Re: Cheapest/Best solution to fix a cracked screen(functional otherwise). My quick opinion: Even if your technically capable of dismantling your phone, the parts may not even be available anymore, you could probably pick up another or even better phone for less than $80- on Craigslist then just transfer your ESN to it.