Not sure how or where to book?

[2manygirls]

We are looking to go to Disney world some time next year. When would be the cheapest time to fly(very open schedule) from Colorado?

Where should we book through travel agent, travelocity, the airline itself or somewhere else?
Should we wait till it gets close to the date we decide to fly & try to book or do it right away?
If we book right away & the flight gets cheaper will they refund/credit any money back?
If my DD is 2 do I buy her a ticket or can she sit in my lap for free?


Thanks!