Thanks for the responses, everyone. I had a feeling there was a better way to do this (that would avoid opening up a browser window and messing with all of that), and it sounds like HTTP Post might be it.

Details: I'm trying to automate buying and selling player cards in the online marketplace of the MLB The Show video game. There is an online marketplace that allows you create orders to buy and sell players. I'm more just curious if I can get it to work than anything else. Right now I'm trying to buy, but selling will be identical.

I've been reading about HTTP Post, but I'm sure I'm not going about it the right way. The page is at http://theshownation.com/market/buy_order?id=[player's id number]. Here is the relevant part of the source code (I think):

<form action='/market/create_buy_order' class='buy_order_form' method='post'>
<input name='authenticity_token' type='hidden' value='[long string of characters]'>
<input name='price' type='text'>
<input name='listing_id' type='hidden' value='[player's id number]'>
<input class="button" name="commit" onclick="return confirm(&#x27;Are you sure you want to create this buy order? The required funds will be taken immediately.&#x27;)" type="submit" value="Create Buy Order" />
</form>

So far on my task, I have:

Server:Port
http://www.theshownation.com

Path
/market/create_buy_order

Data / File
authenticity_token=[long string of characters]
listing_id=[player's id]
price=[some number]

Thanks again for the help and the tips. If there's more info I can provide that would be useful, let me know!