Rinnie and Sarah gave you very good advice. There are some online dealers who will sell you cameras at incredible prices, then ask you to buy accessories at a super premium (i.e. exorbitant) price. Go to www.pricegrabber.com
and look at the prices for dealers with more than 100 good (4 or 5 out of 5) ratings. Don't buy accessories unless you have checked the prices of the similar accessories at a brick and mortar store. For online accessories, I like www.newegg.com
but there are other places with good reputations and service to match. Here's my tale of rip off. I bought a superzoom camera 6 years ago. Got it at a good price. Also got a 2X teleconverter for over $100, "normally" $200, according to the salesman. Well, actually, that teleconverter cost less than $40 on Ebay. Now it costs less than 30 bucks. It magnifies, true, but also distorts. Not a great photographic accessory.
Get your Olympus E-500 or Pentax K110d or K100d or whatever from a reputable dealer. However, don't fall for the fast talk about fantastic deals on accessories from salespeople on a commission.