1. YaPromo
  2. Guides
  3. Promo Codes Explained: Types, Limits and Stacking Rules

GuideUpdated YaPromo editorial team

Promo Codes Explained: Types, Limits and Stacking Rules

A promo code is a store-issued discount that is checked against rules at checkout: what it takes off, which items and sellers it covers, which country and account it belongs to, and when it expires. Most big stores allow only one code per order, and many codes exclude sale items, gift cards, delivery and marketplace sellers. Reading those rules before you shop is the quickest way to know what you will actually save.

The main types of discount

Stores describe their offers in different ways, but almost every code falls into one of a few types. SHEIN's US Coupon Policy is a useful reference because it lists them plainly: fixed-amount coupons, a percentage off the whole order, a percentage off non-sale items only, and free shipping.

  • Percentage off. Takes a share off the eligible items, for example 10% off. Check whether it applies to the whole basket or only to full-price items.
  • Fixed amount off. Takes a set sum off, often once you reach a minimum spend. On Uber Eats, any unused value on a fixed-amount promo is lost, not carried over (Uber Eats help).
  • Free shipping. Removes the delivery charge. At ASOS, free-delivery codes count as your one code for the order, according to search summaries of its help page; we could not load the page itself to confirm.
  • Cashback. Not a code at all. You pay full price and money comes back later, through a cashback site or a payment app. Cashback and codes often conflict, which our guide to cashback sites explains.
  • Gift with purchase. A free item added when you meet a condition, such as buying a certain product or spending above a threshold. The same reading rules apply: check the threshold and whether stock is limited.

Minimum spend, item limits and caps

Most codes come with conditions that decide whether they apply and how much they take off.

  • Minimum spend. SHEIN coupons can carry a minimum spend. If you return part of an order and what you keep falls below that minimum, SHEIN may reduce your refund by the coupon's value (SHEIN US).
  • Item-specific offers. On Amazon UK, an item-specific offer can only be redeemed against that item (Amazon UK terms).
  • Seller limits. Amazon UK promotional codes only come off eligible items sold and dispatched by Amazon.co.uk, not third-party sellers or Amazon Resale (Amazon UK help). SHEIN coupons only work on third-party seller products marked as eligible.
  • Things codes never cover. Amazon UK codes cannot be used on gift cards, Audible products, delivery costs or gift wrap. Amazon's US help page, which we could only read in a search summary, also lists sales tax, Prime fees and extra shipping.
  • Caps. Some percentage codes have a maximum discount written in their terms. If a code seems to take off less than expected, look for a cap before assuming it failed.

One code per order is the norm

Several major stores state outright that you can only use one code at a time:

  • Amazon UK: one code or reward per order unless the offer says otherwise, and codes cannot be added to existing orders (terms).
  • SHEIN US: one coupon per order, with no stacking.
  • Uber Eats: one promo per order, and promos cannot be combined (help page).

Codes are usually single-use too. On Amazon UK, a code used on an order you later return for a refund cannot be reused, but if you cancel the order the code goes back to your balance straight away. SHEIN restores a coupon when you cancel or return the full order, unless it has expired or was never linked to your account.

New-customer and account-linked codes

Some codes are tied to who you are, not just what you buy. Uber Eats says some promos are limited to certain users, such as first-time customers (Uber Eats). SHEIN separates coupons that are linked to your account, which show under Personal Center > My Assets > My Coupons, from those that are not, such as homepage and influencer coupons.

Search summaries of ASOS's help page say emailed codes may be tied to the account they were sent to; the page itself would not load for us. If a code came by email, sign in with that same account before applying it.

Why codes are country-specific

Stores run separate sites, prices, currencies and promotions for each market, so a code is usually built for one of them. SHEIN says its US coupons can only be used on us.shein.com and the SHEIN US app. Uber Eats says a promo only works in its stated location and currency, and some are limited to certain cities, states or countries (Uber Eats). UNiDAYS says its codes only work in their own country (UNiDAYS).

Rules can differ between a brand's own country sites too. Amazon UK and Amazon US publish separate help pages, and SHEIN's UK and UAE rules may not match the US policy. When shopping in the UAE, Saudi Arabia, India or the UK, use a code issued for that country's site.

Stacking with sales and student discounts

Whether a code works on top of a sale or a student discount depends on the store:

  • SHEIN has a coupon type that only applies to non-sale items.
  • Uber Eats applies merchant promos first, then automatically adds your highest-value account promo. You can choose a different promo or none.
  • Nike's US student code can only be combined with free-shipping codes (Nike).
  • Samsung US says its education savings can be combined with public and seasonal offers (Samsung).
  • UNiDAYS notes that brands can exclude sale items from student codes.
  • Amazon UK's Buy Now button cannot be used with a promotional claim code, so go through the basket instead.

Reading "was" prices and countdowns

A discount is only as real as the starting price. In the US, the FTC's pricing guides say a former price is genuine only if the item was really offered at that price, regularly, for a reasonably substantial period. A price inflated just so it can be cut is fictitious (16 CFR 233.1).

In the UK, the DMCC Act's unfair-practices rules have applied since 6 April 2025. The CMA's guidance says falsely claiming an offer is only available for a limited time is banned, for example a countdown timer that resets, and that a discount ad can mislead even when technically accurate (CMA207). Mandatory fees must be included in the headline price (CMA209).

Questions people ask

Can I use two promo codes on one order?

Usually not. Amazon UK, SHEIN US and Uber Eats all state one code or promo per order. A few stores let a student or member discount combine with a free-shipping code, as Nike does for its US student code.

Do promo codes work on sale items?

It depends on the code. Some apply to the whole order, others only to full-price items. SHEIN, for example, has a coupon type limited to non-sale items. The terms on the code say which.

Why does a code work in one country but not another?

Stores run separate sites and promotions per market. SHEIN US coupons only work on the US site and app, and Uber Eats promos only work in their stated location and currency.

Do I get my code back if I return the order?

It varies. Amazon UK returns the code if you cancel, but not if you return the order for a refund. SHEIN restores it for a full cancellation or return if it has not expired and was linked to your account.

Sources

Rules and fees change. Each figure above was read on the official page on the date shown; the provider's own page is always the final word.