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

1881 Liberty Head Half Eagle Five Dollar Gold Coin $420.01

WTC 911 Ground Zero Recovery 1991 PCGS MS69 $50 Dollar Gold Eagle $4,995.95

1899 $10 Ten Dollar Gold Eagle $949.00

1/10 Oz. 1996 Solid Gold $5 Dollar Eagle Sealed No reserve $198.50

1882 LIBERTY EAGLE $10 TEN DOLLAR GOLD COIN $861.54

2006 $10 Dollar 1/4oz Ounce Fine Gold Eagle Gem First Strike PCGS Certified MS69 $604.95

2003 $10 Dollar 1/4oz Ounce Fine Gold American Eagle Gem BU PCGS Certified MS69 $599.95

2003 $10 Dollar 1/4oz Ounce Fine Gold American Eagle Gem BU PCGS Certified MS69 $599.95

1888 LIBERTY EAGLE $10 TEN DOLLAR GOLD COIN $865.54

GOLD 1910 $2 1/2 DOLLAR QUARTER EAGLE GOLD COIN AU NICE COIN $294.80

1886-S LIBERTY HEAD HALF EAGLE FIVE DOLLAR NICE GOLD COIN .. $499.00

1887-S LIBERTY HEAD HALF EAGLE $5.FIVE DOLLARS GOLD NICE COIN $499.99

1882-S LIBERTY HEAD HALF EAGLE $5.DOLLARS GOLD COIN XF FREE SHIP… $499.00

1993 US Gold American Eagle 50 Dollar Coin FREE SHIPPING!! $1,810.00

Gold on Silver Morgan Dollar Reverse Eagle Necklace RB $246.99