I've read that you could buy, then sell, then re-buy the same item to attain this. For me, I actually didn't have to struggle with this, as I mostly bought Stardust for upgrading Talismans. You may struggle with some funds early on, but at least make sure you're searching for Talismans to sell at a later time (and also performing all of Sandra's Rites as you get a Talisman for every character anyway). The only real Talisman I'd suggest keeping is the Cur Fang, as it is needed for another trophy; beyond that, sell and buy, repeat.
Later on in the game, you'll actually acquire two replenishable sources of income in your blackwagon that will produce a berry and mushroom after every major rite (read: probably just Liberations). They don't sell for much, but it does give you a bit more than you previously had, which is something.