I live in Canada. Say I want to use adwords to market some clickbank products.
Do I need to register a business to deduct my adwords cost from my affiliate sales? Or can I just deduct advertising costs for my year end internet profits, but just as a person, not a business?

not sure about canada law, but for a US tax return you can deduct all your expenses related to your internet income (including adwords expenses) on a simple schedule C which does not require any business filing, you can do it as a sole proprietor.

I am not sure about Canada. But here in the US I would set up an LLC or a sole proprietor. Both can be filled on your personal taxes as a schedule C. I would recommend getting QuickBooks Pro to help set everything up. My accountant put my ad words as marketing expense. I have done this now for 5 years in a row. Been audited once and I was all good. That was only because I went from working for someone else to working for myself and let’s just say I more than tripled my income.
But if you want to do this full time I would call and talk to a local accountant and lawyer and they will let you know what the best options for you are. I traded services when I first started out. I built both of them a web site. I say it’s better to play it safe.

And yes if I miss spelled any words that’s cool with me because I know I can’t spell. I am not paid to spell. Lmao.

BRady