SOLVED. Children's Chapter book about two siblings(?) secretly buying a horse. [s]

[Laura]

I'm pretty sure the protagonists were an older sister and younger brother who wanted a horse. Their mother said no, but the siblings found a cheap horse somehow (I think through the Classifieds in the local newspaper), saved up some money, and purchased it secretly.

They found somewhere to board the horse and one of the other boarders is an unfriendly man but, if I remember correctly, he becomes a bit friendlier after his horse gets it head stuck between a fence or a stall door while trying to get some hay or something and passes away.

The protagonists' family was poor and at some point during the story, either their heat, power, or water was turned off, only to be turned back on after the mother calls somebody and manages to get it tuned back on after tugging on some heartstrings

I believe the mother did eventually find out about the horse, but the children were allowed to keep it.

I read this book while I was in elementary school, so that would've been in the mid to late 2000s. It was a paperback written in English and I'm not 100% sure, but I think that the cover may have had a grey/white horse in a stall on it

[Stephanie]

No Small Thing

[Laura]

Stephanie wrote: "No Small Thing"

That's it! Thank you!