There is no set figure. The amount should be proportionate to the cost of this enterprise and supported by a plan that can move the stock under current terms. Review the purchase contract's refund, escrow and cancellation clauses, since not every deposit is capital genuinely at risk.
Price the risk, not just the order
Ask what happens if the milestone is missed: is the stock returnable, is pricing renegotiated, does the territory shrink? Then budget separately for premises, staff, working capital and the case itself, and confirm government charges as current when each step arrives. No spending level guarantees approval, and no projection guarantees a return. Reserve periods used in planning are examples, not legal requirements.
The valuable work here is judgement: reading the refund clause, deciding which payments count toward the committed total, and testing whether the revised plan still supports a non-marginal enterprise. Substantiality is assessed proportionally: the amount invested is compared with the total cost of establishing a business of this kind, and the proportion must be high enough to show the investor’s financial commitment and the likely success of the enterprise. Substantiality is measured in proportion to the total cost of purchasing an established enterprise or of creating a viable new one, so a modest sum can be substantial for a small operation and a large sum insufficient for a capital-heavy one.