
The riskiest financial decision at the start is the quantity of your first order. A large quantity locks up your money, and a very small one may raise the price per piece.
An order of 600 pieces, and you expect to sell 30 a week, so you need about 20 weeks to sell it (600 ÷ 30). If that is longer than your money or the season can bear, reduce the quantity or open another sales channel.
If the supplier allows a smaller trial batch at a slightly higher price, it may be worth it, because it teaches you before you commit to the full quantity.
Work out the number of weeks to sell your first order under three weekly sales scenarios: cautious, middle and optimistic.