Hard to say, but none of the 77/series are cheap. Older rimfire models have slip-fit barrels held with a clamp like a 10/22. That lets you replace them with aftermarket barrels or even switch cartridges. Newer ones have barrels threaded into the receiver.
I've played with three 77/22s, all .22LRs. All were decent shooters with ammo they liked. The target model like yours was the best, due in part I'm sure to the Timney replacement sear kit that I installed. Since my main use for a .22 is hunting and rifle practice, I value handling, reliability, and looks a bit more than bug-hole accuracy. I sold a very accurate CZ 453 to help pay for the 77/22 RSI I hunt with now and wouldn't go back, even though the new one won't group with the CZ. It's handier in the field, looks better, and the last one I saw for sale was listed for $200 more than I paid for mine (which was plenty).
If you're looking for a really accurate rifle for targets or tiny varmints like ground squirrels, you can probably get something that will shoot as well or better than the one you're looking at for less money. For the stuff that a .22 mag is really made to do, hunting small game and medium-sized vermin, the 77/22 is a good choice, very solid, and reliable, and in my opinion, a pleasure to handle. They also hold their value well.
Check actual bids and final selling prices on Gunbroker for a good estimate of what you should pay. The same model also comes in .17 HMR, .22 Hornet, .17 WSM, and .17 Hornet if you're not dead set on a .22 WMR. WMR ammo has been hard to find lately and expensive.
