Here are my requirements: 1. I need end of day data for: - all US option chains once per day (end of day data). There are about 3000 optionable equities on US exchanges, so thats 3000 put chains and 3000 call chains per day. - select option chains in real time at various points throughout the day. - stock quotes to go along with all the chains in 2) or 3). 2. I'd like to be able to access the data using a web URL and have it returned as an XML object. My application is built using Ruby on Rails and I go on to store everything in a MySQL database. 3. Low cost! I'm still in development. Thanks.