[Update] They worked with me and offered me a decent refund for this "service tax", but none of this would be necessary if I had booked through the hotel directly. I would advise doing that.
I booked a hotel for work. $105 per night at the Holiday Inn, 3 nights. I got my hotel bill after my stay, $335. It wasn't until I saw my credit card charge of $485 when I realized something was up. Apparently this was due to GetARoom's "tax recovery charges and service fees." They offered me $35 off of this bill as "a sign of goodwill." Now I have to explain to the boss why I paid nearly $500 for a 3 night stay at a cheap hotel. Avoid, avoid, avoid.