Donations
Yasst is free to download and use.
Yasst is a one man hobby project, which I work on in my spare time, and you are completely free to download and use it as you like, however, if you like it and you think it's worth a few quid donation, then here's a big yellow Paypal button to click on... ;)
BTW, if you don't have a paypal account and don't want to sign up there's a small 'continue' link in the midde of the page for credit cards.