I went to NY last year for a couple of Jays games. When I went we stayed in the Bronx because all of the hotels in Manhatten were sold out. I'd suggest seeing if you can find a Groupon for a Manhatten hotel if you can as it seems like you could get a decent deal in advance. As for tickets best bet is seatgeek.com. You usually can find tickets below face value but might not be the case with the Season Opener. Yankees prices are really expensive compared to other places around MLB.