Recommended library for linear programming in .Net? [closed]

Question

Can anyone recommend a library - free, or commercial but affordable (

There are some listed here: http://en.wikipedia.org/wiki/Linear_programming#Solvers_and_scripting_.28programming.29_languages

....but I am just starting out with LP and hope someone can recommend something.

I am trying to basically minimize pricing for cell phone subscription services.
I guess the 1st question is: is linear programming even applicable to solving this problem?

A simplified example:

Base Plan Options
Plan A: 200 Voice minutes, 10 Text Messages, 10 MB Data = $25
Plan B: 400 Voice minutes, 25 Text Messages, 25 MB Data = $40
Plan C: 1000 Voice minutes, 50 Text Messages, 50 MB Data = $65
...
Plan F: 2500 Voice minutes, 150 Text Messages, 150 MB Data = $95

Charges for exceeding your plan (for all cases):
$.10 per voice minute
$.20 per text message
$1.50 per MB Data

Optional Add-On Packages (added to Base Plan):
Free Weekends $15
Free Evenings and Weekends (after 8PM) $20
Free Evenings and Weekends (after 6PM) $35 Text Message Package #1 (50 Text Messages) $5
Text Message Package #2 (150 Text Messages) $10
Data Package #1 (20 MB Data) $20
Data Package #2 (50 MB Data) $30
Chatty User Mixed Pack #1 (100 Minutes Voice, 100 Text Messages) $15
Geeky User Mixed Pack #1 (50 Minutes Voice, 150 MB Data) $35
etc, etc etc

I have a set of detailed usage data for 50 users, and want to figure out which combination of base plan (A, B, C ... F) each person should be on, as well as which add-on packages(s) they should have.

Answer 1

Check out the GNU Linear Programming Kit.

http://www.gnu.org/software/glpk/

Answer 2

You can try Microsoft Solver Foundation. It is a mathematical programming library, which supports solving linear programming, mixed integer programming, stochastic programming, and other optimization and modeling problems.

It is available in Express (Free), Standard, and Enterprise (MSDN Subscriptions) editions.