I have the Sims 2 Ultimate Collection and I love building/playing apartments. In all my previous apartments, I added solar panels (and such things) to the common areas so my sims actually GOT money instead of having to pay bills. So I decided to take it a step further and be totally cheap, reducing individual apartments to 3x6 rooms with a bed, desk, and bathroom. Everything else I put in the common area.
On one lot, I loaded the common area with tons of awesome stuff (including solar panels and whatnot) and then had my sim rent a furnished mini-apartment for about 100 simoleons. Her bills were 26k+! So then I had her rent an unfurnished. Still 26k+. So I made a new lot, smaller and with cheaper common area stuff. 22k+ bills now... better, but still wtf! I specifically did not want to have to motherlode this sim or cheat their bills away.
Is this normal? Are my apartment lots just way too big/fancy? Is she being charged for using common area stuff? What is going on? This doesn't happen in my self-contained apartments.
I is so confuse. :/

It might have to do with the solar panels. The common area shouldn't affect an apartment. Try moving the sim out, then fix the lot by moving panels to the apartment property, roof or whatever area belongs to said apartment. I remember reading somewhere that using too many panels can have an opposite affect by adding to bills, instead of subtracting. (:

The greeting cards... Do you have the Postal System mod?

You can't place those though unless you have a sim on lot I think? Do they really have a high nominal value?

The problem is not the greeting cards, but something with the postal system mod which is necessary to send the cards can cause 26k bills.
Ref. this thread http://modthesims.info/t/576530

Oh now you say it, I remember reading about that. I thought there was also a fix for it?

If not, I wonder if the magic wand would reset the lot value?