No set number.
I buy a rifle I like, scope I like but don't "pair" them to cost.
Bergara with a Leupold
Ruger with Nikon
Montana with SWFA
That's my outlook on it too. My rifles have specific purposes and I scope them accordingly. Big game rifles get 2-8Xs or 3-10Xs, sometimes 3-12X. Varmint rifles are outfitted with 6-20X or 6-24X, or maybe a 5-20X in one case. I like very accurate rimfires fo paper punching and mine have 3-15X Super Slams on them. My .375 Big Bore is set up with aperture sights and my muzzle loader wears a 1.5-5X.
I prefer simpler reticles, so there are a couple of varmint type BDC reticles, and everything else is a plain old duplex. I find complex reticles somewhat distracting.