ReceiptPal is a receipt scanning app like Receipt Hog, but you can send your e-receipts for online purchases and the points add up faster. You can earn up to 300 points per week. I forward all my e-receipts to them from my Amazon purchases and Google Play purchases. The best exchange of points per dollar is 19000 points for $100 Amazon gift card, Visa gift card, or PayPal cash (but PayPal potentially charges fees for it).
Another thing to consider: Receipts over 14 days old when scanned will be rejected. Make sure to scan all your receipts before they “expire”, not just to reach the 300 point max per week, but also because each scanned receipt that is accepted counts as an entry to their weekly $250 giveaway.
At the end of each month, scan any receipts you have for purchases from that month. They allow you to scan them up to the 3rd day of the following month but then do not accept any receipts from the previous month after that. I will scan everything I have the last day of each month so I don’t miss out on potential entries for the $250 giveaway they have for that week.