I swear by Clark Howard's book, Living Large in Lean Times. He offers the absolute best advice with website links so you can start saving and spending smartly.
I purchase things online, just like you do. But, I really love a discount. I first stop by Retailmenot.com for promo codes and web coupons. Then, I view the retailer's clearance and/or sale sections. Lastly, I view regular priced items. For a retailer like Jos A Banks, men should check online first and foremost since there are very deep discounts there, not in the store.
I have tried doing a web search for the words coupon and the retailer's name. This always results in questionable sites and sometimes viruses. I trust the retailer's site, like Target, to send me coupons directly to my email once I sign up on the site. I definitely use Kiirkland's for that reason.
If at all possible, select the ship to store option during checkout. I do that for retailers I live and work near. This all results in free shipping!
Lastly, visit retailer sites, select items you want, and come back to your shopping cart another day. Please delay your urge to checkout the same day. I often review the cart items later and realized I saved myself from bad taste.
Let me know what online shopping tricks you have.