Glad to hear that you are interested in hunting with crossbows. The pricing varies with brand and fps. Barnett and horton are going to be your cheapest brands. I like to have a crossbow that shoots at least 300 fps. A buck commander or predator by barnett will cost you antwhere from 550 to 700. I personally like the jacka - cant beat it for $250. Anyways, you will find lots of bad reviews and comments regarding barnetts products. however, they have starting making great strides to reverse this reputation by offering a five year warranty on all 2010 and 2011 products.
With that said, your Parker crossbows are going to be an extra hundred dollars or so more expensive that the previously mentioned bows. The tornado is a awesome xbow for the price - somewhere in the neighboorhood of 600 to 700 dollars. But with a parker, you get a lifetime warranty. So that kind of makes up for the elevated price. They have great customer service that will get you up and running if anything happens to break.
Then you have your excaliburs and ten points. As you probably already know, these are the flagship or top brands in the market for quality and high standards. im sure the warranties with these two companies are spot on with parker. they are pretty expensive - I believe the cheapest excalibur - a recurve crossbow manufacturere btw - will cost around 550 dollars.
Ten point also makes a cheaper brand called Wicked Ridge. The cheapest model by WR is around 400 dollars I believe.
The bottome line is this: you need to set a price range and then see if you can test shoot a cb at a store like gander mountain, cabelas, or bass pro.
Hope this helped