Um, no, that doesn't sound right at all to me, as both a blogger who hosts giveaways occasionally, and a shop owner. I really would not pay them at all, ESPECIALLY $100, that's insane! Sometimes you have to pay like $80 for a premium ad spot, and that will include an ad on the blog or website, tweets throughout the month, an exclusive giveaway spot and so on, but you NEVER give them an additional present along with that $80. And bear in mind that that $80 is along the lines of a pretty amazing blog with a very, very strong following, 5000+
I think, however you look at it, if you've already payed her, you've been ripped off big time. She doesn't seem interested in helping to promote your shop, just getting free stuff for doing next to nothing. The $100 is more than enough, and it would cover several items from your shop if she really wanted something.
Another question I'd have to ask is this: is she expecting you to send HER the giveaway prize? Because that's a no-no as well in my book. It's far too easy for a blogger to keep the item herself. At least if you're responsible for posting it to the winner, you can respect your work and make sure it's going where it's supposed to, rather than potentially being stolen, which would give the winner a bad opinion of your shop because you "never posted it".
In my opinion, get your money back and run. It seems a bit too dodgy to me.
