Okay, I have tried in the past the "Buy me a Beer (or coffee)" donation plugin on my blogs.

Never made a great amount of money, let me tell you!

Have you used this on your blog, or still use it?

How about a new alternative (not new, about 2 years old, but I just got it earlier on another forum)?

The Donations Cloud Zirona

From the site:

The Donations Cloud – donating the 2.0 way!

The donations cloud is something like a tag cloud, only that it displays – donations. The more a person donates, the larger the link to his/her website will be. (A special function ensures that small donations aren’t to tiny, and very big donations aren’t ridicioulusly large.) To see a “live” donations cloud, have a look at the sidbar of this page.

I have this set up on the 3 blogs I will be keeping.
I set it up so minimum donation is $2.00 (default is $5).
Plus set it up that the links stay up for 120 days (default is 30 days).
And the links are do-follow.

See it on the sidebars of:
Random Ramblings from Iowa | XRMO.COM
The Iowadawg Shizzle Blawg
The General Blogger | Blogging Anything

Of course, you can really check out how it works by donating????