Commas and $ in datatable columns

Hi,

I have a datatable with 4 columns that hold currency. Currently I'm treating them as normal columns and manually appending '$' to each value. Now I need to format the column to have commas as well. Is there any plug-in to do this? I also want to remove the manual addition of '$' value. I checked few sites, but I really didn't understand how they work. Thanks a lot for help.
-Maddy