Big 5 Sporting Goods has weekly sales on shoes and boots. This week they have two boots you may be interested in.
The first is the MEN’S RESPONSE GEAR ‘ZIP WP’ 8” WATERPROOF SERVICE BOOT
The price is listed at $39.99. Unlike some of their other boots with a combination of textile material and leather, this one is solid leather. It is also waterproof.
The other is the Smith&Wesson Tactic Boot. Similar in appearance to the picture above and isn't posted on their website. The price is marked down to $59. It's an excellent quality boot and waterproof. I know...I've worn my last ones for two years in a lot of rain.
If you sign up for their email newsletters, you can get 10% off the price at checkout.
IMHO, unless you go all out for a "real" riding boot with shin and ankle protection built in, these boots are a great buy for a riding boot.