So i found this website called exedecompiler.com that has a few services like code modification or development, and a service that stands out is the "exe to source code" for $50. Has anybody used it or heard about it?

Is it worth $50 for a decompilation into source code?

If i really want to decompile an exe are there "better" alternatives or maybe a service like this is a good idea?

Please give me your thoughts about it.

EDIT:

To clarify my goal on what I want to achieve. The application is a GUI application that in short, operates with the contents of a binary (non executable) file. I am not shure what the source language is, my guesses are C++ since the app interacts with an embedded system, but nothing is confirmed (I'm shure It is not .NET at least, no luck for me)

My goal is not something simple like changing an IP address, as something like a hex editor could maybe do the job. The two main goals would be analyze a certain functionality and to add extra functionality.

I would like to analyze a portion of the code to discover how this executable manipulates the memory given to it (the file contents) and discover what "magic" it does to it.

I would also like to either change some of its code to add extra functionality, but i find this to be harder and unlikely. So i thought of doing some DLL injection that would execute the code i need, that being adding extra UI components to the GUI that would do what i want, but didn't succeed yet in achieving my goal. I am studying what exactly went wrong as it didn't seem to be something obvious like bad code or no permissions.

Thank you for u/NaughtyBlackGuy that recomended Ghidra. It seems like the tool i was looking for. I am not a reverse engineering expert but I know a thing or two and its never too late to learn.

If somebody has any other tips or tricks I would gladly take anything else i can take.