Inexpensive, plastic poker chips are available just about anywhere. Higher end chips can be purchased at gaming stores and from a variety of online sources such as these:

PokerShopping.com
www.pokershopping.com
PokerShopping.com specializes in high quality, affordable poker chips and poker chip sets, with fast and cheap shipping. The site is comprehensive, accessible and offers many varieties of chips and chip sets. PokerShopping.com has a new Swedish language site, www.pokershopping.se

Poker Chip Mart
www.pokerchipmart.com
Poker Chip Mart offers affordable prices and full selection of chips, chip sets, chip cases, poker tables, cards and other gaming supplies.

Pokerchips.com
www.pokerchips.com
Pokerchips.com has a very good selection of supplies including poker chips, poker chip cases, poker chip sets, tables, good background information on poker and great customer support. Prices seem to be a little on the high side.

The Poker Supply Store
www.thepokersupplystore.com
The Poker Supply Store offers close to everything in poker supplies including chips, chip sets and cases. The site is easily navigated and the prices are moderate.

Poker Bargains
www.pokerbargains.com
Poker Bargain offers a wide selection of poker supplies including poker chips, poker books, sets, cases, and accessories. Well designed site and low prices!
Poker Chips Info provides detailed information about the history and types of poker chips, as well as poker chips cases and sets, and advice on where to buy poker chips. Poker Chips Info is the sister site of Pool Tables Web.