Scrape together $50-$100, and go to some yard sales/thrift stores in the next month. Buy GREAT CONDITION children's clothes, boys if you can find them, good brands (Gymbo, Janie and Jack, boutique if you can find it, Gap, ON, just make sure it is in GREAT shape). You can find them for $.25 - $1.00 each at garage sales, around $2-4 at thrift stores. You could even look on Craigslist for a lot of clothes. Just make sure they are in great shape.
Go to consignmentmommies.com and use their search feature to find consignment sales coming up near you (fall sales are starting now!).
Register for a GOOD one (look for the Consignment Mommies awards), and you will turn that $50-100 into $300 or more.
This is not FAST money, but it is GOOD money. Flexible with your schedule.
I've been doing this for a couple of seasons (investing far more than $50) and it's paying off big time.