Take a look at your SFI goals and review them, adjust your plan to include $500 as your investment.
Consider when you want to see a return on your investment and how much profit do you want.
Allocate this $500 to cover your financial expenses over a period of time.
These are ways you can invest financially.
Invest in a standing order for:
1- PSA-To-Go
2-S-Builder Co-op
3-125 Tcredits
Invest some in driving traffic to your TripleClicks gateways to generate sales.
Invest in your own website/blog and your own domain name.
I wouldn't advice spending $500 all at once, spread it out over a period of time. As time goes by you may need to make changes to your plan in order to reach your goals. The changes may have a cost, you want to be able to pay for these costs.