Save your money and just download OpenTerminal or grab this pack of finder toolbar buttons (one of which is open terminal here) provided free and open source on github.com
If you have an account and want to just download the buttons here is a direct link: "https://github.com/Orangenhain/Finder-Toolbar-Items/downloads" but you should check out the source too or at least see how you can make the toolbar buttons do even more by going to the main part of the url I posted, just leave off the /downloads part.
I didn't make these, I just find them very useful and they are free and open source. Please do NOT pay for this. Unoriginal idea, free version available, plus to make it even worse it is MAS.
Get the same thing, actually more, for free above. We can't let "devs" get away with charging for apps that are free and have been out already for years produced by many different people sharing their work. This .99$ toolbar script is a joke.