Getting Hyip referral via ppc? good?

Hello, recently i started and join a few of the Hyip sites.

So im thinking is ppc worth the money for the conversion?
or
should i go for cpm as cpm is way cheaper than ppc? But people told me nowadays most cpm is just for brand building as most people don't click on it.

If ppc worth the money, can anyone recommend me good/legit/real human traffic site? Seen alot complaint on most of the ppc site as they provide not genuine/fake/hitleap/bot traffic.

Thanks