It's difficult to say as a lot depends on your specific use case and what you print and on which paper.

For my main use case, I bought a 100-pack of relatively inexpensive satin a3+ poster paper (so only 280g, but eh, they get put on the wall with something like poster strips or tack, I hardly need them to be thicker) which comes down to ~78cents per sheet. Ink usage is difficult to measure because my prints differ wildly in how much color is on them but my average so far seems to be ~50 cents per max quality a3+ print. So ~€1,30 per full size print if I want to be slightly pessimistic about it. But some of them were probably more like 85 cents total. 😅

The ink bottles really last a long time. Check your local prices but over here they cost €22 a bottle to replace, the printer has two blacks (one is pigment based for documents and stationary and so on), CMY and a 60% Gray, they all cost the same here but might be different for you. And then of course depends on what you print.

What I sadly cannot say is what A3 would cost, but scaling down you should be looking at roughly 20% less ink costs per print for full-size graphics prints, and then of course the paper you're printing on. But that's just mathing it down from my A3+ prints.