Priceline hotel bidding: Once you bid can you reject their offer or are you automatically locked in?

From the website, it seems fairly clear that once you bid, and if your bid is accepted, that you're credit card is immediately charged and you are "locked in" for that hotel. Just wanted to confirm that this is the case. Would also be interested in hearing if anyone else has had positive or negative experiences using priceline. Thanks.

Once your bid is accepted your credit card has already been charged, but you save a lot of money.

I'm going to Fort Lauderdale in a few days. I used Priceline and got a room at a Sheraton for 4 nights.

By booking direct with Sheraton.com I would have paid $1,038.96 USD.

By using Expedia.com I would have paid $913.51 USD.

By using Priceline's name your own price I got the room for $368.76 USD.

I always use Priceline, you save big ... but always book 1 star over what you really want, that way you won't be disappointed.

Why 1 star over what you really want?

A 3 star hotel that was built in 2008 kind of looks like a 4 star that was built in the 70s, and with Priceline you never know what you're going to get.

So the worst 4 star hotel is good enough for someone who was expecting a 3 star.