Colorescience has several deals running at once, but the best choice depends on your basket size. The main offer is 10% off orders over $50, which rewards larger purchases, though there are other paths to savings for different shopping situations.
Small basket under $50: If you're picking up a single product or your order comes to less than $50, the flat 10% off your purchase deal works well and beats waiting to hit the higher threshold. Alternatively, signing up to the newsletter gets you access to special offers and promotions, which is a smart move if you plan to shop with Colorescience again.
Basket of $50 or more: Once you hit $50, switch to the 10% off orders over $50 deal instead. Both offers give you 10%, so there's no difference in discount percentage, but you might as well use the offer that explicitly rewards this spend level.
Shopping during a sale: Colorescience runs sales with up to 30% off, which will beat the standard 10% discounts if the products you want are included. Check whether your items are on the sale list before deciding—if they are, this is your best option.
Making repeat purchases: The free gift on your 3rd order is worth factoring in if you're a regular shopper. It's not a dollar discount, but a complimentary item does add real value once you've placed a couple of orders.
Subscription savings: If you're interested in placing regular orders, the up to 15% subscription deal could be worth exploring alongside the other offers.
Only one offer applies at checkout, so compare what's available in your basket and pick whichever gives you the biggest saving. If you're not yet a Colorescience shopper, signing up to the newsletter first is a good habit, since special promotions often go to subscribers before they hit the wider site.