Best Refferal Programs?

I'm wondering what are the best referral programs, to advertise and make money off of? any ideas?

Hosting used to be the best, but not anymore so alleviate the hassle by finding something new.

Free samples are a good niche idea alongside a majority of programs in spedofic sector like eCigs, adult etc...

Find a new gold rush and jump into it. Cryptocurrencies are a hit pick too.

Its all about HOW you advertise it
As long as the product, whatever it is have demand you are good to go.