If you are looking for Priceline help this is the correct forum. If you have other questions about cheap transatlantic travel, then other forums might have answers but for PL strategies this is the right place.
As fuel costs rise tickets are likely to cost more not less this summer. Add in the summer olympics and flights are definitely impacted
If you don't care when you go or how long it takes to get there (i.e. 12 hour layovers, different airlines etc) then PL can be a fine resource. Why NOT bid as low as you want and see what happens?
You might also look at
www.betterbidding.com
and
www.biddingfortravel.com
to get a sense of what other winning bids have been.