Madison, If you return the rings that came with the rifle to Ruger they will exchange them free of charge - whatever they make: 30mm rings, stainless, extra high, etc. I've done this myself several times, takes about 3-4 weeks to get your new rings. All you pay is the two bucks or so it takes to mail the rings to Ruger (I think they ask that you send $5 for S&H but I never have and they still always send me the new rings).
I've used the Millett, Burris, and Warne rings for Rugers, the real Ruger Rings are still the best IMO. After that I'd go with Burris, their Ruger ring is pretty nice. Warne rings are excellent but even more expensive than real Ruger rings. I haven't had good luck with Millett, the ring is well made but I don't like the way they attach - the tiny screws they use can be easily over-torqued and broken. -- Kernel