With the updates to the Windows Marketplace for Mobile one of the new capabilities added was the ability to view applications in other markets. With the new found capability I've seen that some users have tried to switch to the USA marketplace and are led to believe that the USA marketplace has a certain number of applications. The number that the user concludes is always less than the number of applications actually available in the USA marketplace.
Within the developer dashboard a developer can set the prie that customers in other markets see when viewing the application. These prices do not have to be the same after currency conversions, so I could set the price of an item in the USA market to be 1.99 USD for the SA market and free for some other market.
If I don't set the price for the application at all for a market then that Market won't be able to see the applcation. So this is another factor to consider if you are unable to see an application in the Marketplace.