Horse Trading in 1916

I found this little book some place. I don't even remember where it came from. Probably some box lot from an auction, or stashed in a box of postcards dug out of the attic when we moved in, or who knows where else I could have gotten it. Today I peeked in it and realized there was this letter stuck in it's front pages and I never knew it. It reads:

Louisa, VA
May 11, 1916

Dear Robert.
I want to thank you for the many nice things you have done for me lately. The box got to Louisa with Gipp all right. She looked so pretty. After Hugh Goodwin knew he would buy at $135 he backed out after I got her here. I think he thought he would get her for $100 but - he didn't. 
Suppose Mr. Covington told you all the Lousia news. J.W. got home yesterday. Tad is also expected soon and Josie comes latter part of the week. Would be glad to have you come to see them any time. 

Very Sincerely,

Mildred -

I figure Gipp was a horse - a pretty mare. So she arrived in a "box" - I figure, a truck with tall sides on it, that they  used to transport horses in before horse trailers; or a box car on a train. Nearest I can figure.
Hugh wanted to buy her, but Mildred wouldn't come off of $135; so Hugh left empty handed. And Mildred sounded pretty proud of herself. Robert had probably advised her not to take anything less than $135 or she'd be a fool.
Or. I thought, maybe Gipp was a dog. A dog could arrive in a "box". But I can't see anyone paying $100 or even $135 for a dog in 1916. That amount of money seems more reasonable for a horse. 
So I am sticking with the horse story.

I just love things like this. I only wish there was a photo to go along with it - so I could see the pretty Gipp and her gutsy owner, Mildred.