Cost for developer to create .IMP file from excel into AR sales invoice?

SOLVED

Good Afternoon:

Our company runs on a pretty small budget. I have been reading "How to Import Sales Invoices from external format". I need a third party developer to write this file for me. The actual import seems pretty straightforward after that.

I am wondering if anyone out there has used this service and what it cost you. The cost could be prohibitive of me delving into this any further.

Thanks

Cathy