Things are noticeably quieter on the Las Vegas Strip these days, and casinos usually known to boast excess are dropping prices to cope with a bad economy that has hit Sin City particularly hard. It might seem weird, since people generally think one thing when they come to Las Vegas: Big money. But enough inexpensive fun exists here to fill a trip without stinging stakes. Examples: $45 rooms at the Monte Carlo, slow-paced poker games, and free attractions, from lion-watching to a manmade volcano.