How to create a drivers for WEC2013 without using platform builder?

I have to build a dll containing a very specific drivers, from the begining of my dev I used a trial platform builder version but now this trial period is over.
Do you a solution to build a drivers without using platform builder or do I have to buy a licence ?

Actually a WinCE driver is a regular DLL exporting symbols with well defined names. Nothing prevent you from building that with Visual Studio application builder.
There are two issues:

you can’t debug (or debugging would be complex to setup, at least, if the driver can be loaded in user mode).

if the driver needs to be loaded early during boot you may have to configure the image to load and mount the flash driver earlier than usual (this on imx6 and 7, on tegra is not needed)