(co-founder here) The lion's share of those costs are related to drafting the investment agreements. It is a lengthy process if you want to do it properly, especially if you haven't done it before. Usually you sign a term sheet first that roughly outlines the content of the agreement. The devil is in the details though, so the full agreement may take a couple of weeks to finish. Then there is due diligence, option pool, and a bunch of other stuff to consider before the deal is sealed.