I don't like getting stuck with needles, but I still give blood.  I did yesterday, in a church basement near work.

I love giving blood because, aside from not costing me any money, it is incredibly efficient.  Money donations are often completely wasted, or used for some purpose other than you intend, or are used in some ineffective way.  Blood is different.

1. Blood isn't fungible.  That is, it can really only be used for putting into someone else's body and not for any other purpose.  So you know where it's going.  I suppose someone could sell it, and thus turn it into fungible money, but I don't hear of that, not in this country.
2. Blood can't be used for fun.  Relatedly, no is tempted to go on a tear with blood.  Most people, actually, don't want the stuff around.
3. Blood can't be used to pay administrative costs.  Most charities spend huge quantities, perhaps most of the money they get, to pay salaries, marketing costs, office rents, etc. etc.
4. Blood is something people really need.  You don't have to worry that your aid is being poured into some useless dam or training course or anything else with an unknown or negative outcome.
5. Blood is something people really need.  And there isn't enough of it.  The people who need it, really need it, in an immediate and clear way.
6. You can always make more.  If you're healthy, you keep cranking out those red blood cells and plasma anyway.  In the end, it really doesn't cost you anything.

When you give money, you often have no idea of what you're giving, and who you're giving it to.  With blood, you're hitting the target.

The Red Cross has improved its processes in the past few years, but I still think they could revamp their marketing and outreach, and get their donation rates up substantially.  But that's for another time.