Which version of Crystal Reports and/or Runtime to purchase

Crystal for Visual Studio is free.  No need to purchase.  Just download and install.

Instead of asking the developer to create a viewer application, consider getting one of the free or inexpensive 3rd-party viewers listed at http://kenhamady.com/bookmarks.html

Don't we have to purchase Visual Studio for each desktop?

An application deployed to a desktop doesn't need Visual Studio. Talk to your developer -- he/she should be able to clarify these things for you.  Or, again, reduce complexity & expense by simply getting a 3rd-party viewer.

Agree.  For 10 users you will need 10 copies of one of the viewers.  Ido's DataLink viewer is an excellent choice

Direct link
http://www.milletsoftware.com/DataLink_Viewer.htm

A 10-user license is $150.  There is no way you could develop even a simple viewer for that cost.

Ken Hamady reviews the viewers each year.  His latest review is here
http://kenhamady.com/cru/comparisons/crystal-reports-viewers

mlmcc

I agree. It doesn't make sense to develop your own software. It will be expensive and will take time. It is much cheaper and you will get way more features if you purchase an existing software.
You can check the features of most of the available viewers in this PDF: http://kenhamady.com/viewerfeaturematrix.pdf

Keep in mind that purchasing the software is not the main expense. The main expense is the maintenance. You pay for the software once , but you pay to the people who are using it and support it every month. How are you going to add new or updated reports. Some viewers will require to go to each computer in order to do this. For 10 users and 5 minutes per computer you will have almost an hour for each report. So for each new or updated report you are going to pay 1 hour wage.  In my area this will be $70-$100. For 10-15 reports this will go easily over $1000. There are some viewers , which are designed to work in a network and the reports will be added from a central place . These viewers will save you time and money.  Another important feature is reports' permissions. I guess you will have few regular employees, for example sellers, and at least one manager. The sellers will use reports to see customer data, and the manager will use reports to check sellers performance. You do not want sellers to be able to run reports for managers, right? So, as you can see, there are things that are not obvious and you will find them when you start using the software. If you develop you own software you can add the feature, but if you purchase 3rd party software it will be either supported or not. Then you may need to change the software. My advice is to get few viewers and to test them in a network environment ( at least 2-3 machines). For 2-3 days you will find the software, which serves your needs best. Or who knows, you may find that a Desktop application is not the best choice for you and you need to try a web based solution.

Thanks to all but this is like the game where you whisper in one person's ear, they pass it to the next person and eventually it comes out something totally different.

All I really wanted to know is this...if I purchase one developer edition of Crystal can it generate "runtime" versions that users can use without purchasing more copies of Crystal...I gather from all your answers that the answer is "yes" with a viewer.