In general, circulated Eisenhower Dollars aren't really worth anything more than $1. There are a couple varieties that are rare and have some value...but in general no. People think they are novelty...but that's about it.
Not at all...you paid face value for them, they will always be worth that. If you want to look through them for varieties...maybe you will find something.
Here is a great example. There are 3 different "types" of the 1972 (P) Ike Dollar. Type 1 and 3 are common...type 2 has value. If you have any 1972 (P) coins...you could check for any type 2s. Look here for info: http://www.coincommunity.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=28637