He said that he owns ZERO files, so the cost of the files is going to be factored into the build. Plus a refret requires even more specialized tools. Once you buy them you own them, but any cutting tools require sharpening and wear down and at some point need to be replaced. Especially anyone who is building for profit has to figure in some money to cover overhead such as tool where, sharpenings, electricity. He is starting with his first build so there is no thought of profit at this point, but his credit card won't know the difference of tools or parts.
As for a first build, it is safe to say that $150 to $300 is a safe estimate depending on the brand and quality of parts that you buy for the guitar alone. If you have to pay some one else to do some of the work, then that will cost more. The pricing for tools can range greatly, it again depends on brand and quality, but also what you already own. The first few builds always drain the most money from your pocket since you are buying the tools. If you have a very limited tool box you can easily drop $500 in tools without thinking about it, but it is best to look at the list of required tools that is pinned and decide what you NEED and what you WANT. I started with very minimal tools and bought my first neck because it was a ton cheaper than buying all of the tools for fretting and creating string nuts.