Eisenhower Dollars are not rare but there's some condition rarities that have been certified by the top grading services like PCGS (refer to list above). However most "Ike" dollars found are worth $1 but if they're uncirculated then they can bring over $1 raw. Also there's several dates and mints that were clad in 40% silver and they can be valued up to at least $8 to $10 depending on current silver melt and grade is also a factor, but not all Eisenhower Dollars are made of silver. Here's the details on identifying the silver from the copper-nickel clad.
"Ike" Dollars also provide the collector with some varieties to cherry pick: 1972 Type 1, 2, 3 Earths (Type 2 is most valuable), 1976 (1776-1976 due al date) Type 1, 2 reverses which is bold and thin letters of UNITED STATES OF AMERICA, and then there's the "Peg" Leg, 1971-S "Tiger Claw", 1971-D "Friendly" Eagle, and some silver dates and mints that should not have been struck in silver to look for.