For current Las Vegas chips I would recommend Andy Hughes ( nevadacasinochips.com ). I think he has the best prices for $5 Las Vegas LE'S and House Chips. Chuck Smorse also sells Nevada chips cheap, and runs a "new issue service" for newly released chips. Either is a great choice, and both are fast and easy to deal with.
For price guides, The Chip Rack (TCR), and The Official US Casino Chip Price Guide are good choices.