I can't speak for allowing purchases, I don't recall any issues back when I bought it. And I'm not really sure how much plainer the purchase info could be, since it's right there on the side of the page between "Purchasing" and the button that says "$ Buy Now!"

The Pro versions of our software are available for personal, non-commercial use at only $10 for 90 days, or $36 for 365 days, for use on up to 5 PCs! Purchasing any of our products also gives you access to all of our other current products! Buy it now!
And also on the other side between "Download Inner Space" and the button that says "Download Now!"

Inner Space requires a Gaming Tools Pro subscription.
Register a Lavish Software account
Purchase a subscription or apply for a FREE 7-day trial
Download and go!
Or @ http://isboxer.com/ where it says

ISBoxer is free multiboxing software for Lavish Software's Inner Space. Get everything you need now for just $36 per year or $10 for 90 days!
or http://isboxer.com/index.php/get-isboxer

To purchase and download everything you need to get started just like in the video, here's what to do!
Register a Lavish Software account
Purchase a subscription or apply for a FREE 7-day trial
Install ISBoxer and Inner Space with our new ISBoxer Bundle installer
Use ISBoxer's Quick Setup Wizard as shown in the video, and play!

The links in Get ISBoxer Now! menu to the left (below the main menu) can be used (instead of the links above) to follow these instructions without leaving ISBoxer.com.
or in the menu on the same page

Get ISBoxer now!
Register a Lavish Software account
Purchase a Lavish Software subscription
Or apply for a FREE 7-day trial
Download and install ISBoxer and Inner Space
I don't even use the software, but it's certainly not for lack of being able to find out how to get it.