Are you looking for a specific brand recommendation? or rifle type?
There are a few ways you could go. It depends on what you are looking for and what purpose the gun will serve.
Ruger Mini 14. Around $650. Good reliable gun that has fair accuracy.
Keltec. SU-16 Cheap, very cheap. They offer several different .223 semi autos. But you get what you pay for. $500 or less. I have never been too happy with their pistols. They work most of the time and shoot okay at best. Some people love them.
FN and HK .223's are higher than the price range. These companies get great reviews on most of their products
Ar-15. Everyone makes one. Most are around $1000.
If you want an AR, look into Bravo. They offer the best gun for your money. They are as good as Colt, Daniel Defense, LMT and Noveske, but they do not have as high of a price tag.
Bravo lower. $300
Bravo upper. $400
Bravo BCG. $140
Bravo charging handle. $50
Plastic Magpul hand guard. $30
Rear Magpul Sight $60?
So if you go with an Ar15 and get the bravo, then you would spend less than $1000 and have one of the best quality Ar's without the $1500+ price tag. The bravo Ar's are military spec, and are higher quality than the Commercial spec Ar's that a lot of big named companies have lowered their standards to.
If I wanted a semi auto .223 I would get either an Ar-15 or the Ruger Mini 14.