Incorporating will keep your personal assets protected in the event of a lawsuit. You really have to access the likelihood of someone suing you to determine if it's necsessary. You don't have to use an attorney; there are plenty of online incorporation services available.
Obtaining a business license is typically a city ordinance to comply with. If you're renting retail or office space, it's a must. If you're operating out-of-home, you can get away without one. So long as you're not seeing clients or receiving a high volume of deliveries, you won't attract attention. But it's usually not that expensive, and some cities do not even charge a fee. So IMO, it's worth obtaining one to be legal.
There are some different ramifications, tax-wise, between an LLC, S-Corp and a C-Corp, so be sure to talk to a CPA.
Although you don't necessarily need a lawyer to setup an LLC, if you don't manage your LLC properly it won't be worth the paper it's written on.
Evidently it's common practice to get LLCs thrown out on technicalities so plaintiffs can go after your personal assets. The advice our lawyer gave us regarding things we can and cannot do within the structure of an LLC to help prevent that possibility has been extremely useful.