Need some help from Friends and Readers

I am a person who likes a good used book sale or the book section of the Salvation Army or Goodwill.  I always look for books from the Travis McGee series by John D. MacDonald.     There are only 21 books in the series, but I am always on the lookout for them. I am looking for copies with the original cover art, but will take any copies.  So if you come across any please pick them up for me.

Thanks in advance….