I tried to use Priceline a few weeks ago to get a hotel in New Orleans. They didn't like my offered price and wouldn't let me try again for 3 days. I won't be trying again.

I do get frequent email from travel companies with good deals one of them is:
http://www.travelzoo.com/top20

There are lots of other ones also.

I have found that the best overall prices are found on Travelocity. That does not mean I book everything thru them but I do get the prices from there. When searching always use the Flexible flying times button. There can be a huge difference in prices and all you have to do is read the terms and conditions section to see when those prices are good. It is well worth it to save $200 per person and end up leaving a few hours (or days) earlier or later. I then know what the lowest curent price is. I usually call the airline involved directly because they can sometimes get you better connections. (I normally have to do this since most of my flights are on bump certificates and only the airlines can book flights using them).

The bad news with Priceline is that you have to make an offer which will be higher than their minimum acceptable. So you always pay too much.