Something that looks/feels/sounds/tastes/smells “like a million bucks/dollars” is something that is wonderful or excellent. “A good dinner looked like a million dollars to me then” was cited in print in 1911. A million dollars was—and still is—a large sum of personal wealth.
 
“Like a million dollars” as popularized in the songs “I Feel Like a Million Dollars” for the movie Million Dollar Melody (1933) and “I’m Feeling like a Million” for the movie Broadway Melody of 1938 (1937).
 
“It must suck when billionaires wake up feeling like a million bucks” is a joke on the expression.
 
 
(Oxford English Dictionary)
million, adj. and n.
colloq. (chiefly N. Amer.). (like) a million dollars (also bucks) : extremely good or attractive; wonderful, splendid, excellent. Usually preceded by to feel (or look).
1911 C. G. Roe Prodigal Daughter 58   A good dinner looked like a million dollars to me then.
1925 P. G. Wodehouse Carry on, Jeeves iii. 55   It was one of those topping mornings, and I had just climbed out from under the cold shower feeling like a million dollars.
1933 E. E. Cummings eimi 109   Something which might be port..‘Looks like a million dollars’—and which tastes like awfully watered vino rosso à l’américain.
   
2 August 1912, Hutchinson (KS) News, “Those Freaky Styles,” pg. 10, col. 7:
“It’s the best looking gown you’ve got. Looks like a million dollars.”
 
HathiTrust Digital Library
Savitar
Columbia, MO: University of Missouri
Volume 21
1915
Pg. 288 (“Heard in the Ladies’ Parlor”):
“It’s perfectly wonderful, divine—looks like a million dollars!”
 
Google News Archive
25 March 1918, Gettysburg (PA) Times, “Military Police On Every Night,” pg. 1, col. 1:
“Do we like it? Say, after Upton, this place looks like a million dollars.”
 
8 October 1919, Boston (MA) Daily Globe, “Great Uphill Fight Gives White Sox Victory in 10th” by James C. O’Leary, pg. 1:
Reuther, who looked like a million dollars in the opening game, did not look like so much money this afternoon.
 
HathiTrust Digital Library
Behind the Motion-Picture Screen
By Austin C. Lescarboura.
New York, NY: Scientific American Pub. Co.
1919
Pg. 102:
Some players require practically no makeup, while others have to spend much time appearing before the camera, lacking as they do a “camera face,” or a face that “photographs like a million dollars,” to fall back on studio parlance.
 
OCLC WorldCat record
Feel like a million!
Author: Will Waldron; A.H. Lewis Medicine Company.
Publisher: St. Louis, Mo. : A.H. Lewis Medicine Co., ©1928.
Edition/Format:   Musical score : Popular music : English
 
OCLC WorldCat record
I feel like a million dollars : featured in the educational musical comedy “Million dollar melody”
Author: James F Hanley; Benny Davis; Art McKay
Publisher: New York : Movietone Music Corp. : Sam Fox Pub. Co., sole agents, ©1934.
Edition/Format:   Musical score : Fantasias : English
   
OCLC WorldCat record
I’m feeling like a million (from the MGM picture “Broadway melody of 1938”)
Author: Nacio Herb Brown; Arthur Freed; Glen Gray; Pee Wee Hunt; Kenny Sargent; All authors
Publisher: United States : Decca, [1937]
Edition/Format:   Music : 78 rpm : Jazz : English
 
OCLC WorldCat record
Foods can make you feel like a million!
Author: Catharyn Elwood
Publisher: Washington, Better Nutrition Institute, ©1952.
Edition/Format:   Book : English
 
OCLC WorldCat record
How to buy a fur that makes you look like a million : expert advice for finding the best fur value
Author: Viola Sylbert; Carol Tonsing
Publisher: New York : Villard Books, 1986.
Edition/Format:   Book : English : 1st ed
 
OCLC WorldCat record
How to sound like a million dollars : turning your everyday voice into an asset
Author: Lyle Vernon Mayer
Publisher: New York : Walker, 1986.
Edition/Format:   Book : English
 
OCLC WorldCat record
Dress like a million (on considerably less) : a trend-proof guide to real fashion
Author: Leah Feldon
Publisher: New York : Villard Books, 1993.
Edition/Format:   Book : English : 1st ed
Summary:
Help for developing a look that is effortless, hassle-free, relatively inexpensive, in tune with the times, and that complements your individual personality, figure type, and lifestyle.