Just booked our flights to go to the US in November - £269 return from Heathrow to JFK. American Airlines sale until July 14th Cracking price, figured we wouldn't get cheaper to go over for Thanksgiving. http://www.americanairlines.co.uk/aa/i18nForward.do?locale=en_GB&p=/specialOffers/fareSale3.jsp
Stay more East or North in Manhattan and don't use the big chains cos they're all a rip off. If you're going at the weekend there's usually bargains to be had in the business district but obviously it's a bit quiet round there when the offices are all shut.
A few I've stayed in - have a look online for Red Roof Inns, they are a chain at reasonable prices. Hotel Pennsylvania on 7th Ave is ok, across the road from Madison Square Garden and also Penn Station which is very handy if you are getting the train from the airport. NY though isn't a cheap place for hotels! We aren't staying in NY but travelling down to Philadelphia to visit family.