vbscript debugger

If you're referring to "classic" VBScript, i.e. .vbs files, Microsoft has a tool available called Microsoft Script Debugger that functions more or less like a Visual Studio debugging session. It's probably your most lightweight option short of adding debug statements to the code.

VBSEdit is great.

The free version does have an annoying timer but it's $59. It does use Microsoft Script Debugger.