Directly. The substantiality test compares the amount invested with the total cost of buying or establishing the enterprise, so a lower-priced business requires a higher proportion of the price to be invested. There is no fixed minimum; application and professional costs are additional.
A cheaper business needs a bigger share paid from the buyer's own capital
The regulations describe a proportionality test rather than a threshold. The investment must be substantial in relation to the total cost of purchasing an established enterprise or creating a new one. In practice, a business costing a modest amount needs to be almost entirely funded by the investor's own committed capital, while a much larger enterprise can be acquired with a smaller proportion because the absolute commitment is already large.
Hypothetical example: a Sainte-Brigitte-de-Laval roofing contractor considers two U.S. targets, a small crew business at a low price and a larger company with equipment and staff at several times the price. For the small business, nearly all of the price must come from his own funds or personally secured borrowing; for the larger one, a seller note or bank loan secured on his Québec property could fund part.
Beyond the investment, budget for the consular application fee or the USCIS change-of-status fee, a business valuation, a business plan addressing marginality, an accountant for the source-of-funds record, legal fees.