"Oh You Little Darling!" and a 19th century Michigan variety store

This vintage advertising trade card, circa 1890, measures about 2¾ inches by 4¼ inches, though it has clearly been trimmed at the edges with scissors.

Can anyone identify the musical instrument that the red-cheeked man is playing? I'm no expert, so my best guess is something like a baritone horn or euphonium. (My first thought, before doing some Google searches, was "backwards saxophone," but I knew if I actually typed that phrase here in the blog, it would just make me look silly. So I didn't.)

The back of the card contains more mystery. Someone, long ago, added together a long string of numbers — prices, probably — to arrive at a grand total. There's also a very faint stamp. The part I can make out states:

FROM
CONGER'S VARIETY STORE
ST. [????], MICH.

The word after "ST." is only four or five letters long, and appears to start with a C, D or O. My best educated guess, and it's a strong one, is "St. Clair." For that, I can thank Suzanne Wesbrook Frantz, who has transcribed excerpts from the St. Clair, Michigan, newspapers for the St. Clair Historical Museum.

Here are some relevant excerpts from her excerpts:

• March 1888: "Conger & Co. have decided on the removal of their variety store from their present Jay street location to the Front street stroe recently vacated by G. B. & J. A. Forrester in the Sheldon block. They expect to open up business in their new quarters as soon as April 1st."
• April 1888: "Conger’s New Store – The opening of Conger’s new store last Thursday was in every was a decided success. The large salesroom was filled with goods, both useful and ornamental, which set off the store to excellent advantage, and the surprisingly low prices at which everything is offered furnishes a temptation to buy which few can resist. Almost every line is represented, including hardware, tinware, crockery, glassware, fancy goods, jewelry, toilet articles and everthing else usually found in a variety store..."
• May 1888: "During the week the front of the bank and of Conger’s and Ingles’ stores have received fresh coats of paint and have been decidedly improved."
• August 1888: "A. L. Conger, of Kalamazoo, is spending a few days in the city the guest of his parents, Mr. and Mrs. A. Conger."
• February 1889: "Miss Zula Conger on Monday left for Richmond where she has a position in the new Variety Store."
• January 1891: "W. H. Conger, of Port Huron, formerly in the Conger variety store in St. Clair, is to be wedded on Tuesday next to Miss Jennie Sutton, an attractive and popular Richmond young lady."
• March 1891: "Mrs. and Mrs. W. H. Conger, of Port Huron, visited Aaron Conger and family a portion of this week."
• April 1891: "H. E. Lovejoy, the popular Lenox auctioneer, did the selling at the Conger auction sale on Saturday afternoon and evening. The sales were well patronized and the entire stock was nearly disposed of." ... "Chas. Feldmeyer purchased the piano at the Conger auction sale on Saturday last for $12. Emil Feske at the same time purchased an organette. What the boys have in their minds we are unable to state. The latter in all probability will furnish music to his customers during leisure moments."

It appears that there might have been more than one Conger's Variety Store in Michigan. There are also references to a boat or barge named Conger.

As a final note, the only other example I found of this particular Victorian trade card online is at the Toronto Public Library's website.