If you recently purchased from Google Express [google.com]
double check the TAX charge, it's possible they may have overcharged you.
I am posting this under Hot Deals (admins can move), so it's noticeable and not overlooked. Also, I would consider it a Hot Deal when money comes back to you.
I got onto the Groupon & AMEX statement credit bandwagon. I noticed that on all my receipts, I was being charged about 12% tax instead of the shipping location at 8% tax. In my case, it was over $15 so I pursued. You will need to verify shipping location (not where you live) to confirm the tax overcharge. Customer service was quick to correct the mistake and gave me the credit, but I want others to know and double check their receipts.