So carrying around artifacts in your inventory gets expensive very quickly once the bills roll in, or at least that's what I assume caused my sim's bills to skyrocket. Fortunately, once she got back from her vacation, she's also able to bring in 4000+ per day just by authenticating the artifacts sent to her in the mail. I don't know if these two things are meant to balance one another; I've sold the majority of my collection at this point and am just wallowing in filthy lucre.
The frugal trait only "reduces" bills. I remember when World Adventures came out in the sims 3, they added a "no bills ever" reward, and if you wanted to keep a large collection of relics and such you really needed that. How are people's bills looking, and what are you keeping? Has anyone kept complete artifact collections, and if so, what are your bills like?