Liveaboard is definitely the best way to go in Raja Ampat, but you'll still get amazing dives in no matter where you stay. A liveaboard will take you to sites that are out of range for the day boats, so you'll get to see a lot more.
If you're not looking to spend $5000 USD on an 8-day trip (even though the Arenui and Dewi are amazing boats), I would recommend looking at Wicked Diving. I went with them last December on their 9-day Raja trip and had a great time. Just FYI - Wicked Diving is a budget liveaboard (around $2000 for the trip), so you'll be sharing a cabin with another person, and the boat is relatively small - if you've ever stayed in a hostel, it's a very similar vibe.
However, you can also stay at a homestay or dive resort in Raja Ampat for extremely cheap and still have amazing diving! For example, the Kri Homestay is something like $60 USD/night for 3 meals a day, a small bungalow, and several dives a day on nearby dive sites (such as the house reef, Yenbuba jetty, Cape Kri, and the manta cleaning station near Arborek).
Yenbuba jetty was, by far, my favorite dive site of the trip - insane numbers of fish, huge coral gardens, and lots of interesting creatures (we even had a school of 20-30 devil rays circle us for an entire dive). The Kri house reef also makes for excellent diving - I saw blue-ringed octopi, wobbegong sharks, and the Raja Ampat walking shark here, just to name a few.
Contacting some of the homestays can be a little tricky, so just message me if you'd like help. Good luck!
