Every month, my husband and I each get an "allowance" of discretionary funds. That money is ours to do with whatever we want, no questions asked. It gets auto-transferred into our individual accounts - he saves his, and I spend mine.
I've got a bad habit of being a supply collector ... er,
hoarder. I thought when I moved from physical supplies to digital ones, I'd be better about using them - no more worrying about saving a favorite supply "for the perfect page". I'm still just as bad, though - at last count, I own over 1200 digital kits. Have I made 1200 scrapbook pages? No, of course not. I probably have more digital supplies than I could use in a lifetime... when I came to that realization, I changed my approach to shopping. For now, I'm only buying kits for which I have an immediate project. Like, something I'm going to start within the next month. Not, "Oh, this would be great for that Hawaii album from our trip 10 years ago that I'd like to make someday..." That's how I get myself in trouble. <sigh>
What has worked well for me is using Pinterest as my "free shopping cart". I set up a board for Kits I Want and started pinning away. Every time I got an email newsletter, if I loved a kit and had the urge to buy it, I'd pin it instead. Then when the big sales happen in May and November for iNSD and iDSD or Black Friday, I could go through and get them on big-time sale.
And as you're stretching your stash, be sure to consider recoloring elements to maximize the pages you can use them with. HTH!