Plan on doing more maintenance than just lifters. First you could try to rebuild them. Likely one of them just got plugged up and is starved for oil. But on the other hand, you are that far down, and it's a bit of work to get that far in. So if you can get a set of injectors for a decent price it would be an all right idea to replace them all and save yourself some work. If you don't mind the work, then try rebuilding first. If it works for you, then you've saved yourself a lot of money!
I have heard of additives you can add also before tearing it down. Like ForceFedTT mentioned. It's worth a shot!