It's not the cheapest script, I'll agree there - but the UI is excellent, the ability to queue purchases is great, and I didn't need to baby-sit it. For me, the simplicity of use and not having to fucking touch MTA made it well worthwhile.
If Eagle's is the only script, I think you can try and put a competing script out there though. I'm not a scripter and I have no aspirations of becoming one though, so I haven't really looked into the rules and agreements about that.