The way I was buying shipping materials was way too expensive. I was running to the local Walgreens and picking up a manila bubble wrap envelope ($1.29) or a small box ($1.99).. combine that with the actual postage, I was around $4.00 for the most expensive option. I do credit back any overages on my shipping, but it was pretty close at $4. I wasn't shipping very often because I just didn't put stuff up on ebay. But now that I'm in a store, and I need to generate income from my smalls during the week, ebay is a necessity.
Also, my hot wheels that are currently listed is in packaging, not loose. Takes more than just a drop in an envelope and out the door to preserve the cardboard package.
I went ahead and bought several smaller boxes through ebay to accommodate the hot wheels that I have up now, should work well for other smalls as well!