This is a great question!
You should expect to spend about 10 percent of the money you raise on the costs of the offering, excluding marketing. I'd caution against spending money on marketing but remember it will take a lot of work.
Some legal and accounting costs will have to be paid before you can begin raising money. That would typically be at least $5,000 and could easily total 3 to 5 percent of the offering, depending on your circumstances.
The portal will also charge fees. They vary in structure and size but expect to pay 5 percent or more.