We have a car booked through the expedia.ca site for $124 for a compact for April vacation. I was very nervous too, but the prices are so much better.
Well, about 3 seconds after hitting the accept button, I get a call from my credit card company checking if I made the transaction, no problem. A short while later I called Dollar to see if they had my reservation. Yes, they have it and when I asked her if there will be any additional charges, she said only if I add something at the counter (I had a prepaid car.)
We have received the credit card statement, and everything looks good, the fee for the exchange rate (or whatever it was) was only about $3.00. I'm bringing a copy that shows the car is prepaid.
So, everything looks good. We head out in about 25 days. Since most of our group is traveling by ME, I have a fall back plan. (Myself and another mom are taking the car to the grocery store while the dads take all the kids on the bus.)