Tickets To Europe | Europe Air Fare

I was wondering if anyone knows any cheap airline websites or some kind of coupons since tickets to Europe are over a grand per person. To be exact, I'm looking for a website that offers children to be 18 and under (for a 16-year-old). ... I was wondering when is the best time to buy plane tickets, book hotels... Is it cheaper to do it now or to wait a few months? I don't want to be too last minute (i.e., 2 weeks before the wedding), but would like to cut costs as much as ...