The consular visa application fee published by the Department of State, professional fees for the business case, and the costs of restructuring the deal so the investment qualifies. The largest hidden cost is a purchase agreement signed without an escrow condition, which can leave money at risk before the visa is decided.
The expensive mistakes are contractual, not governmental
Government charges for a consular E-2 application are modest relative to the transaction and are published on the Department of State's fee information; a change of status filed from inside the United States would instead use the USCIS fee schedule. Professional fees cover the business plan review, the source-of-funds presentation and the consular package. The real costs come from sequencing errors.
A buyer who wires the full price to the seller before the visa interview has made the funds irrevocably committed in the way the category wants, but has also lost the ability to recover them if the visa is refused; the escrow conditioned on issuance exists to avoid exactly that. A buyer who signs a fifty-fifty shareholder agreement and later has to buy back shares to establish control pays twice. Budget also for a business-plan preparer if the buyer cannot produce credible projections himself, for US legal work on the asset purchase, and for the accountant who will explain Canadian departure tax and US filing obligations, none of which are immigration fees but all of which arrive in the same year.