You can buy program installers, but these are best for applications which contain several files, dll's, icons, manuals and a installation preview slide show. For the basic Excel application, no run-time or packager exists or what is reported to be one like the microsoft viewer do not allow for the actual operation of the application, you can only view the sheet, change some entries, but not run formulas or macros.
Microsoft to compete with the runtime packagers for other database products does make a pakager, which is included in the developer edition of Office, that will add all the system files and a non-buildable version of Access database applications to a non Office system. This packager is reported to also work to some extent with Excel by Microsoft. I have personally discussed this with the Microsoft development team. In therory it should work, but no one has been able to actually get it to work with a fully populated Excel application, as the library files used in the packager look for commen office files and Access files, so some of the Excel files are ignored by the packager. I have not found any packager for installing Excel applications on a non Excel system.
I have written VBA code to build an application on an Excel system, Build the workbook, forms, buttons, macros and formatting automatically a sample of this was posted by me on the old board a few months back. VBA also will let you write to and update the windows registry, so you could write your own installer, but the system you install to would need to have Excel installed beforehand. JSW