$100 is a little low to get started with paid traffic, can you add any more to start?

I would save you money until you get a bit more a budget going, it will help a lot better to have a budget built up.

Like others said, I would probably focus on building other sources of traffic that are free because a budget that low generally won't get you anywhere. Sometimes it could, but usually some testing is necessary when starting to use paid advertising and $100 is not going to be enough to do efficient testing. But sometimes, $100 can net you some profits, it's just easier if you had a larger budget.

Facebook (extreme targeting options) or Google Adwords.

I Would use your $100 and split it up with 4 or 5 different traffic sources and find one that works best for you. What might work for someone else might not work for you. You're best bet is to experiment

100 bucks might be a bit low to get decent traction, as you'll be running out of funds very quickly. Personally, I would recommend at least £300-400 to get a good solid PPC budget. That way you will have enough room to play with until the commissions come in.

Any questions just let me know
Nick

What do you want to advertise?

Is it your product or an affiliate offer?

You could try looking for a good deal like advertising credit from hosting companies or domain providers, eg. name cheap has some - https://www.namecheap.com/deals.aspx, this way you'd get a little higher budget.

Why do you only have $100 to spend on paid advertising? You have a WSO which claims to teach people to make $500-$5,000 Per Day Online?

It's possible to get started on Facebook Ads with only $100 but it would be difficult if you haven't done it before.