every 5 or 10BTC ... use a new wallet.
i do this.
when you pay ... seller don't know if you have more than 5 or 10 BTC.
Your idea was a good tip of advice, I'll copy your suggestion/idea but instead of 5 bitcoin for every new wallet address I'll make it 10btc each. With that amount I'll save a lot of money.
*sigh* It doesn't cost anything to make a new wallet. What you need is something to secure your wallets. But the best option would just be to secure one wallet extremely securely, as I recommend with a ledger wallet.