Put it away, give it away, throw it away - teaching a 3 yo

I struggle a bit with keeping things "just in case" or because I "got a great deal" or because something is "valuable". I occasionally go through blitzes and throw a lot away, not often enough. I don't think we'd be able to move into a 2 bedroom house - right now, my daughter and I are in a 4 bedroom house. *blush*

Now I have a daughter, she just turned 3 - I put a little tune in her head - when I flip the hourglass (probably good for 4-5 minutes), we have a blitz in the room where we: put it away (back in her play room), give it away (her high chair - we sold it on Craigslist yesterday and she help me carry the "tray" to the woman's car) or throw it away (and yes, the Dora flash cards were a screaming crisis because they were thrown away) - and by the end of the blitz, hopefully there aren't any more things on the floor.

She knows by heart:

Put it away
Give it away
Throw it away

So, I'm trying to start her young to view possessions as transient (to an extent), but that what is very important is worth putting away. We're having a garage sale in a couple of weeks so she'll see her things sold - but, I am using this as a chance for her to collect the money so she can see the "fruits" of her donations and when the garage sale is over, we'll go buy one toy - maybe a kite or something (she's 3, so I am limited in what we can do). It's not meant to be punitive, but for her to see that out goes the old, in comes something else. Not from a materialistic perspective, that one can throw away and buy more, but not to hold onto possessions - "just because".

Any suggestions?

I do have to admit, I've probably become tidier as I've strived to become a role model. I'd love to get to the point in life that we could move to a 2 bedroom house with limited storage with a day's notice as my litmus test of success. I've started that visualization - 48 hours notice to a 2 bedroom house - stay or go?

Any other visualizations I can try?
Games?
Pitfalls? Did anyone suffer as a child when their parents made them get rid of things? Ever since Lindsey was about 18 months, I've openly taken her things out of drawers, gotten her agreement that it was too small and we were donating it. A few times, she went to the storage bin to drag something out, saying it still fit. I didn't fight it, just let her have her way that day. What we have not donated, she will see at the garage sale.

I'm hoping to raise her to be a better person than myself - where her sense of value is in "self" rather than "possessions".

I've lurked on this forum for quite a while - there are so many insightful and wise people that I thought I'd share my situation.