I got the 700K bells storage expansion(it only pushes the capacity from 2400 to 3200)...I'm aiming for the 900K final expansion(which pushes it to 5000). About 60% of my storage is CLOTHES; the rest is between supplies like wood/iron nuggs/stones/fruit/star frags/shells and furniture/wallpaper/rugs/flooring.
The clothes buying won't stop(I was able to wear costumes every day for 2 weeks in October up til Halloween)...
I definitely DO NOT have to worry about the costs of the 900K expansion(I try to ease up on my game play, but I'm ALWAYS grinding for bells); in the early days of me playing my motto was "if it aint nailed down, then I'm selling it"- and now since I found out that most items you get or come across go in your Nook catalog within minutes of you touching it, I dont hold onto stuff if I don't have a current/special use for it. I held onto the arcade games coz those things are like 60K bells to buy, but I've sold other stuff coz I have the bells to get it again if I ever need it and it's in my Nook [shopping]
app/catalog.
EXTRA: Except if it's Saharah's stuff, Gulliver/Gullivarr's stuff, some of the holiday spoils/items, or the real art from Redd- that stuff cannot be bought/sold. I've given all of my villagers a gyroid(and I have about 20 myself), so basically now I've just been selling any duplicates...I've bought duplicates of real art from Redd just to put in my house(when I first started playing I was buying & hanging K.K. albums on my wall coz I didnt know they went into the players...lol).