I'll address these one by one.
First, a service vehicle can be a 100% write-off. Insurance, fuel, maintenance and full CCA depreciation. There is no taxable benefit to a self employed individual in a sole proprietorship. If you have an additional vehicle, say a car, you can deduct a percentage of that car's use as related to business.
You can deduct a minimum 10% of your home expenses (rent, taxes, HLW, cableTV, home phone, financing costs) as eligible business expense. More if you can prove you use more. You can deduct 100% of your home internet and cell phone costs.
If customers come to your home office there is no additional insurance required, your business liability insurance covers your office. (in the case of landscaping -- they are not bringing their lawns over to be cut, likely visits are to discuss business and pay bills).
You get back 100% of the GST you paid on business expenses.
At the end of the day it's no joke. Cut grass and make 60K over the summer as a small business and you will likely pay zero (or near zero) tax. Cut grass as an employee and make 30K -- you will probably pay $10K in income and sales taxes.