I agree with letting your secret pal know that you are going to drop out. Every one has hard times now and then and if you will at least take the time and courtesy to let them know you have to drop out and can't continue, then hopefully no one will get their feelings hurt.
But then again, it's the thought that counts, not how much money you spend. A nice word now and then goes a lllllllloooooonnnnnngggggggg way in my heart!!!!!