Promoting your SFI business to your friends and family is more better for you to start with, for you are comfortable to explain how SFI is to you with your friends and your family.
And, they also can reach you anytime for any questions they have.
To promote SFI to strangers, is quite more challenging. They might not believe or they just dont listen to you. GIft Cards may work on them.
(Sorry about my grammar)
I hope this may help.