Get lucky like me and find a NIB vintage Kahles Helia AH3 -9x42 for $500. That fine CZ rifle will look great and perform VERY well with fine Austrian crafted glass on it.
If you havent decided yet, i have a Leuopold vari x III 6-20 x40 on my CZ527 223, and love it, it may go a little over your budget but worth it. I've had mine over 20 years on my everyday (literally everyday) truck gun so good value in the long run