1) Persist in advertising your TC Store URL. Someone will eventually join SFI under you solely for the discount TC offers, and you will earn from them.
2) Keep advertising SFI and bring in as many members as possible. Eventually, you will start earning and be able to set up a Standing Order, and some of your sponsored members will also do the same.
As with any business, it takes time to build it. The foundations need to be put in place first, no matter what you build.