That's a great question! Your 1971 dollar is known as an Eisenhower Dollar, often called an "Ike" dollar. The value depends heavily on which specific version you have, as there are a few different types from that year.
The most important factor is whether your coin is made of silver or a copper-nickel alloy. Most 1971 Eisenhower dollars that were intended for circulation were made of copper and nickel and are not silver. These were minted in Philadelphia (no mint mark) and Denver (a 'D' mint mark). If your coin is worn from circulation, it is typically worth only its face value of one dollar. If it is in pristine, uncirculated condition, it might be worth a few dollars to a collector.
However, the U.S. Mint also created special collector's versions in 1971 that are 40% silver. These coins were all minted in San Francisco and will have an 'S' mint mark on the front, just below President Eisenhower's neck. These silver versions were sold in special government packaging and were not meant for circulation.
A 40% silver 1971-S Eisenhower dollar is worth its silver content at a minimum, which is typically in the range of $8 to $12, depending on the current market price for silver. If it's a "proof" version (with a mirror-like finish) in its original brown box, it can be worth a little more, often in the $10 to $15 range. To get a precise value, the best first step is to check for that 'S' mint mark.
