I've suggested expanding his horse line as there are alot of those folks in the area, usually he has the biggest tack selection at great prices, horse customers always comment on it
I was thinking the same thing. Find products that will sell in the off season.
Then instead of paying for advertising, I suggest creating a newsletter. If you can, make this newsletter digital and distribute it through email. That way, it's absolutely free.
However, perhaps in rural areas, not everyone has email. In which case, having it stuffed in a local small newspaper is usually more cost effective than mail, which has gone through the roof.
And then, there's always a website . . . :-)