How to buy gold – gold dollar versus gold?

Hello, I have an interest to buy gold. However, I am very confused by the different gold coins (American Eagle, American bison) and the gold dollar. Can someone please distribution differences for me? More precisely, is the value of gold as the dollar Gold 2002 (Denver Mint Mark A23) Gold? Why an American eagle cost so much? Thanks

American Eagle because it costs more symbolizes peace and war for America.

The Silver Eagle Dollar

1906 2-1/2 Dollar Liberty Gold Quarter Eagle in 14K Bezel KM72 $299.99

1994 $5 AMERICAN HALF EAGLE GOLD COIN PCGS MS69 MS-69 / FIVE DOLLAR US GOLD COIN $199.95

1915 GOLD $2.50 2 1/2 Quarter Eagle Indian Head Dollar $355.79

2010 $5 Dollar 1/10oz Ounce Gold American Eagle PCGS MS70 Rare First Strike $269.95

1912 US GOLD FIVE DOLLAR INDIAN HEAD HALF-EAGLE **HIGH GRADE** $553.44

2006 W United States Mint $25 Dollar Gold American Eagle Bullion Coin MS69 PCGS $1,699.95

1865-S 2.5 DOLLAR GOLD CORONET LIBERTY COIN~QUARTER EAGLE~SEE PICTURES~ $2,190.00

1989 P Proof Gold American Eagle Five Dollar One-Tenth Ounce $175.00

1913 INDIAN HEAD QUARTER EAGLE $2.5 1/2 DOLLAR GOLD COIN NICE GENUINE $295.95

10 Silver Eagle Airtite Coin Holders & 1 Tube-Tite – Dollar Rounds Gold Bullion $5.99

1929 INDIAN HEAD QUARTER EAGLE $2.5 1/2 DOLLAR GOLD COIN NICE GENUINE $289.95

1875-S QUARTER EAGLE $2 1/2 GOLD DOLLAR COIN NGC XF 45 LOW MINTAGE $400.00

1912 FIVE DOLLAR $5 GOLD HALF EAGLE COIN PERFECT CONDITION!!! $750.00

Authentic Miniature US American Eagle 50 Dollar Gold Piece Certificate FREE SHIP $2.99

1926 Eagle $2.5 dollar Gold Coin $202.50