Small business startup expenses are the costs which you need to spend to get the new business up and running, ready to start producing and selling goods and services.
What you define as startup expenses is completely a matter of opinion. Some costs are clearly one off startup expenses for example legal fees to obtain a lease on new premises. Other costs are not so well defined, for example initial printing and stationary costs might be defined as startup expenses, but at some point printing and stationery becomes a normal day to day trading expense.