LuSol-Guide is EUR 3 (about $3.5 USD). The full version offers unlimited free upgrades. Before you buy it, you can download the free demo version. This version allows you to see if it works with your setup (mount and camera) and also to see how LuSol-Guide works for autoguiding, with a time limitation for autoguiding (60 minutes). Before LuSol-Guide installation, ASCOM platform v6 installation is required : http://ascom-standards.org/Downloads/Index.htm
Then, if you are interested by this software, purchase the full version submitting your payment via the Paypal icon below. The download link to obtain the complete version will be automatically e-mailed to you. For that, please check your e-mail associated with your Paypal account.