Rakuten pays a percentage when you shop online through its portal, Ibotta pays product-specific rebates you activate before shopping, and Fetch pays points for any receipt you photograph.

Rakuten suits online shoppers best with 1 to 10 percent back at major stores, while Ibotta suits brand-loyal grocery shoppers whose rebates stack with sales and coupons.

Fetch earns the least per trip but demands the least effort, since every receipt counts regardless of what you bought.

You can combine apps across channels, and Ibotta plus Fetch can both process the same grocery receipt, but never submit altered or duplicate receipts.

Track each app's actual payouts for a month and keep only the ones whose effort is justified by what they return.