If you list a 99 cent item, and it sells, and you're paid by Paypal, assuming the postage is low, you net something like 27 cents. As postage goes up, that amount goes down since your Paypal fees include postage.
The last time I listed something to start at 99 cents was a few months ago, and I ended up netting about 10 cents. I figured the low start cost would "spur interest". It did not. I ended up the big looser. Due to the high postage cost on the item, I ended up with, like I said, about 10 cents.
10 cents. To shoot pictures, write a listing, package it, and take it to the post office.
What's YOUR time worth?
I will NEVER list another item for 99 cents. I don't start anything below $5, and most items at $9.99. Even at $5, you still end up with only a few bucks.