I would use the internet to find hotels. One of the best things you could do is go to Google and type "cheap hotels Atlantic City." Numerous sites will pop up. There are many hotels on the Boardwalk in Atlantic City and they all try to compete with one another, especially right now during the tough economic times that are going on. It should not be very hard to find a hotel at a decent price. Make sure that you read the reviews of the hotels that interest you first. Like any other city, Atlantic City has areas that you may not want to stay in. I would aim for a hotel that is on the Boardwalk. If you still want to investigate further, you can always contact the chamber of commerce.
I think that this is one area where the internet has become so dominant. It used to be that people could go to a travel agent or some other booking resource and be able to find a cheap hotel or the best rate on one. This is certainly not the case today. The internet has made this a realm where individuals who are persistent can find excellent deals and promotions to lessen the cost of a stay in any place, and is more true with a tourist spot such as Atlantic City. A simple web search would render at least half a dozen such sites. Priceline.com or another such site would be examples here. There is a site listed at the bottom that could also help. The other option would be to call specific hotels and start the negotiation process. I would think that with tourism being so challenged right now with the economy that a savvy consumer could start to discuss prices with different hotels who are competing for your business. If this is not, you check out the online options.
Hotwire and Priceline offer great deals for blind purchases and all sales are nonrefundable. Spend time on Betterbidding.com to learn how to use these sites.