Donn Eisele (1930 - 1987) had one spaceflight -- the command module pilot on Apollo 7. Like some of the earlier crews, there was not a wide variety of photographs available and Eisele never had a formal white space suit portrait. So, collectors seeking signed photos typically settle for the signed business suit pose.
Eisele's earlier signatures tend to be small and neat, while his later signatures are often large, loose and wild.
Expect to pay $200 and up for an Eisele personalized photo, and significantly more for an un-personalized example. On occasion, training poses of Eisele in his space suit come to market and they can fetch a steep premium depending on the quality of the pose. For collectors on a budget, Donn Eisele signed checks are in abundance and can be purchased for around $25 on eBay and elsewhere.
Eisele autopens are common, and obviously, forgeries exist; however, in my experience I have not encountered a high number of Eisele forgeries.