You won't have problems parking in a garage, just make sure your vehicle isn't COMPLETELY secluded. 5$ parking is the norm while some others are 10$ (I.E Tropicana)
Coming from a local, beware at night time.. it can get sketchy - especially on Pacific Ave. You won't have to Valet anywhere either which is a good thing cause they beat your car (comes from experience
The crap casino garages i'd say are Resorts.. it gets tight in there and alot of sketch crap happens there too.. so stay away.
Trump Plaza, Caesars, Showboat, Revel (I forget how much it is but the garage is huge), Taj Mahal shouldn't be bad either.