I have a custom module called Room as well as another custom module called Rehab Costs.  I have a lookup field called Paint Costs in the Room module pointing to the Rehab Costs custom module.  Next to that lookup field, I have a currency field called Painting Costs.  I am trying to write a custom function to pull the Cost field value of the record of the Lookup field and populate the Painting Costs Currency field with that value.  I have been searching and search and not able to find anything to get me what I am looking for.

Thanks for any help with this