Why not? Just wondering because I was looking to go through priceline?
A compact for $263/week is not a bargain. I would expect a compact to eventually wind up at less than $150/week and possibly closer to $100. No guarantee, but that's what I would expect.
Please keep in mind that what I'm going to explain is generally true, but not in all circumstances.
I just checked undiscounted
Alamo compact for 7/17-23. The price is $430. Makes Hotwire/Priceline look good, right? That is a Wednesday thru Tuesday. The rates tend to come down about 7-14 days out. So, change the dates to 6/19-6/25. Also a Wednesday thru Tuesday. The undiscounted Alamo rate is $220. (In fact, you can also get a Dollar city special for those dates at $145 total) Already well below Hotwire and its non-binding. That's 7 days out, which might be a little on the late side...usually around 10 is when you do best.
Does that mean that the Alamo rate will be $220 (or below) for the actual dates? No. Probably better? Yes.
When you quote Hotwire or Priceline this far out, yes, the rate will be less than the going non-binding rate. However, there are almost always discounts to be had on the normal car classes closer to the date, once the agencies see what inventory they have left. It may be true that the 7/17-23 dates may have more demand than the 6/19-25 dates I used as an example, but since we're already into the summer season, I doubt it would be significant.
My advice, as always, is book something non-binding in case rates go up instead of down. Then keep looking and really get vigilant inside the two week window, usually down to about a week. I almost guarantee the rates will go down. I can't remember a time, in my experience, that they haven't.