A house sale is really a large contract agreement with a number of finer points. The legal fees were maybe $750 - 1200 but memory is sketchy on that. There are filings necessary with the state and other items that make it legal, and at least in Massachusetts USA, it is a lot different than say selling a mountain bike. Banks need certain info for loans, there's the deed, etc, inspections, etc.
When you are signing your 20th piece of paper, you realize you needed the lawyer. One dirty secret of realtors is that all this work is handled by lawyers, and the impossible-looking parts of a real estate transaction are handled by lawyers who understand it and have it down to a fixed-price cookie-cutter process for their locality. They did "consult" with me a bit and gave some "free" advice, but I just paid the fix price for doc generation mainly.