What is important to you in a sheepsfoot? Size? Overall cost? Handle material? Lock type? There's so may options. KnifeCenter.com lists 439 knives in stock under $300.
I use knifecenter and bladeHQ websites for their really good filtering options but I rarely buy from them anymore. It definitely helps narrow down the options when companies are releasing so many knives these days.
One I can really recommend if you can get it is the Civivi Chevalier. Button lock flipper with a good size blade and great steel for the price.