I use a 17 hornet for fox....I love the calibre. Its a Savage walking predator model. Its a tack driver and I've killed fox over 200 yards. I mostly take head shots. I shot and hit a coyote right behind the shoulder standing broadside 80 yards away and never found it. I was very confidant in the shot, but after looking long and hard, no fur was found. After that experience, If I'm specifically going our for Yotes, I'll take either my 204 Ruger or my 22-250.
I also use a 204 Ruger 40 gr hornady VMax on fox. I again take head shots and haven't blown one up yet.
I personally am not a big fan of the 223. I would rather step up to a 204 Ruger. I like the bullistics better. I think its faster and more flat shooting over the 223.
JMO...Every assult rifle owner is using the 223 caliber, and as a result, I think ammo is harder to find in the 223. If you reload you own, obviously you can play around with loads to find one you like.
For inexpensive rifles, I would look at both the Savage and the Thompson Center Venture bolt action rifles. I own each and they both preform very well right out of the box, and I am shooting factory Hornady ammo out of both. Both manufactures offer a rifle / scope package for around $500-$550.
If you're spening $275 for the gun, lets not forget now you have to buy rings, and possibly mounts PLUS the scope.....Now your back up to the package priced gun.
I'm sure you will get other opinions on the 223 calibre. I have no experience with the 17 wsm. IF I shot at a yote using teh 17 wsm, I would definitely take a head shot. I say this based upon my experience hitting one with my 17 hornet, which is putting out 3650 fps with a 20 gr Hornady V Max bullet, and never finding it , hitting it in the front shoulder.