"I'm gonna buy me a dog"

[Suzette Haden Elgin]

**Mira Ariel is right -- In "I sold me a dog" the "me" can only be the
seller, not the buyer. "I sold a dog to me" is possible only with strong
contrastive stress on "me," as in "I didn't sell a dog to Tracy, I sold a
dog to ME." (And "I didn't sell a dog to Tracy, I sold a dog to mySELF" is
far more likely.) Similarly, in "I wrote me a letter" the "me" can only be
the writer, not the recipient of the letter.

Suzette Haden Elgin
(native speaker, Ozark English)