The Carlinkit Summer Sale 10% off voucher at the top of this page is the lead offer, and it is best for orders that are not already reduced by a sale and for shoppers who want a guaranteed percentage off at checkout. The code takes 10% off your order online and cannot be combined with any other offers, so it suits straightforward, non sale purchases.
Small purchase of non sale items (under $100, for example), use the 10% off voucher above. On a $80 order, the code takes 10% off (percent 10%), so the final price is $72 and you save $8. The code applies site wide online and is simple when nothing in your cart is in the sale.
Buying selected sale items marked down (items covered by the up to 45% off sale), do not use the 10% voucher; use the sale price. For a selected product showing 45% off, a $120 item becomes $66 (percent 45%), saving $54, which is bigger than the $12 you would save with the 10% voucher on the same $120 item.
A mixed cart with sale and non sale items, compare totals because the 10% voucher cannot be combined with any other offers. If your non sale items form most of the spend, the 10% voucher above may still win. If most of the value is in selected sale items that are heavily reduced, paying the sale prices without the code is likely cheaper. Work out both totals at checkout and take the lower one.
Buying selected items where only the second code applies (10% off selected products), the second code also gives 10% off but is presented for selected items and may apply to sale products per its terms. Because the Summer Sale voucher at the top of this page says it cannot be combined with other offers, prefer the voucher above for a plain sitewide 10% unless the second code specifically targets a sale item you want and the site allows it.
Newsletter signup, sign up if you want future special offers and promotions, but do not treat the newsletter as the main discount option for this purchase.
When choosing, calculate the total both ways: apply the 10% voucher above to the full cart (if you are not buying sale items) and compare that with paying the listed sale prices for selected items. Take whichever leaves the lower total. The code cannot be stacked with other offers, so do not expect it to combine with the up to 45% off sale.