Spanish: Are these "I don't know..." sentences for the verb "to buy" correct?
Yo no se... (I don't know...)

1. si ella se compró el caballo. = whether she bought the horse.

2. quien se compró el caballo. = who bought the horse.

3. que ella se compró. = what she bought.

4. donde ella se compró el caballo. = where she bought the horse.

5. cuando ella se compró el caballo. = when she bought the horse.

6. por que ella se compró el caballo. = why she bought the horse.

7. como ella se compró el caballo. = how she bought the horse.

8. cuantos caballos ella se compró. = how many horses she bought.

9. el nombre del caballo que ella se compró. = the name of the horse that she bought.

10. si ella se quiera comprar el caballo. = whether she wants to buy the horse.

Question

Spanish: Are these "I don't know..." sentences for the verb "to buy" correct?
Yo no se... (I don't know...)

1. si ella se compró el caballo. = whether she bought the horse.

2. quien se compró el caballo. = who bought the horse.

3. que ella se compró. = what she bought.

4. donde ella se compró el caballo. = where she bought the horse.

5. cuando ella se compró el caballo. = when she bought the horse.

6. por que ella se compró el caballo. = why she bought the horse.

7. como ella se compró el caballo. = how she bought the horse.

8. cuantos caballos ella se compró. = how many horses she bought.

9. el nombre del caballo que ella se compró. = the name of the horse that she bought.

10. si ella se quiera comprar el caballo. = whether she wants to buy the horse.

Answer

These sentences sound awkward to me.  At least, in Colombia we use "comprarse" to say to buy something for oneself. For example, Me compré una chaqueta= I bought a jacket (for myself), it's a way to emphasize that you will be the user of what you bought. If you said "Compré una chaqueta", I could ask you "For whom". I guess, the example of the horse make the sentences sound awkward to me. All in all, I would use "comprar" and not "comprarse" in your sentences. It's just my opinion and I might be wrong.

Answer

Hi, Shawn.

I want to commend you on your use of subjunctive mood on number 10. To speculate about a person's desires would call for it. Good job on that!

The verb "comprarse," translates to "to buy oneself/herself/himself/yourself (formal)," which is distinct from "comprar," "to buy." "Se," is a reflexive object pronoun that is used for él, ella, and usted.

#1-10: "She bought herself" - Remember to include the reflexive pronoun in your translation. 
#2: Also remember that an accent mark would sit over the "e" in quién.
#6: "Por qué" means "why?" 
#10: Good use of subjunctive mood here.

Let me know if you have any other questions or would like to schedule a tutoring session.

Michael Monárrez