I downloaded a font (good karma demo) to be exact. Now, I have a small online boutique, and want to use that font in my logo. BUT I'm not sure whether or not I need to pay something for using it in my logo.
I read that dontaionware means you can use the font commercially with the option to pay. However, in the fonts comments, the owner says you'd need to pay to use it. I'm willing to pay for this font, no problem, Though, I want to know ahead of time what does dontaionware actually mean legally just in case I want to use other fonts that say this. Thanks!

I believe the author is very precise when it comes to what he wants. Please see http://www.dafont.com/good-karma.font

I suggest that you get in touch with the author, disclose how you are going to use the font and get the full version which comes with a license to use the font commercially. To give you an idea how much the donation would be, the prices of his fonts at https://www.myfonts.com/foundry/MyHandwritings/ range from $5 to $25.

As for the term donationware, you have to make a donation to use it commercially or any use that is no longer private use. The amount is usually for you to determine unless the author has fixed an amount to donate or the author requests that you get in touch with him first as in the case of Good Karma