It is better for you to start as a sole proprietor as it is cost effective. You do not have to deal with corporation registration and on going cost of compliance with the CRA. Once your business is successful then we can incorporate.
Apart from cost, also consider liability. If you are hiring someone or your contrats with the service provider put you under liability then consider incorporation.
For car, it’s better to lease it as it will make it easy for you to manage cash flow. The lease payments can be deducted as long as they are under $800 per month.