← All guides

How to run flash sales and festival campaigns that actually sell

13 October 2026 · 4 min read · by the Ceylumen team

A flash sale works when three things are true: the discount is real, the deadline is short and visible, and only a few products are included. A festival campaign works when the shop looks and reads like the season and the offers start before the rush, not during it. This guide covers how to plan both.

What a flash sale is

A flash sale is a discount on a small set of products for a short, fixed time, usually a few hours to a few days, with a countdown showing how long is left. The deadline is the point. A sale that never ends is just a lower price.

How to plan a flash sale

  1. Pick the goal. Clearing old stock, bringing in new customers and raising the size of each order are three different sales. Choose one.
  2. Choose a few products. Five to twenty is plenty. Too many and nothing feels special.
  3. Check your margin. Work out the sale price from your cost, not from a round number. Remember delivery and payment fees.
  4. Set a real end time. Twenty-four to seventy-two hours suits most shops. End it when you said you would.
  5. Check your stock. Running out in the first hour disappoints more people than it pleases.
  6. Announce it before it starts. A sale nobody knows about is only a loss of margin.

What the product page should show

  • The sale price and the old price, side by side
  • The saving as a percentage
  • A countdown to the end
  • How many are left, if stock is low
  • The delivery fee, before checkout

Mistakes that kill a flash sale

Mistake Why it hurts
Extending the deadline Customers learn to wait, and the next sale is ignored
Raising the "old" price first People notice, and trust is hard to win back
Discounting everything Nothing stands out, and your margin goes
Forgetting to switch prices back You keep selling at a loss after the sale
No stock check Orders you cannot fill, refunds and bad reviews

The fourth one is common when prices are changed by hand. Use a shop where the sale price ends by itself.

Festival campaigns

A festival campaign is a themed period of offers tied to a season: a new year, a religious festival, a shopping day or a school term. Shoppers expect it, search for it and budget for it, so the question is not whether to take part but how early to start.

A simple timeline

When What to do
Four weeks before Choose products, agree prices, order extra stock
Two weeks before Prepare banners and wording, plan delivery cut-off dates
One week before Tell customers by email, social media and WhatsApp
Campaign days Run the offers, watch stock, answer questions fast
The last day Remind people it ends today
After Put prices back, thank customers, note what sold

Seasons worth planning for

Most shops can use several of these in a year: New Year sales, Valentine's Day, Mother's Day and Father's Day, back to school, Eid, Deepavali, 11.11, Black Friday and Christmas. Shops in Sri Lanka also plan around the Sinhala and Tamil New Year in April and Vesak.

You do not need all of them. Pick the four or five that suit what you sell and do them well.

What to prepare for each campaign

  • A banner and colours for the season
  • A campaign page that collects the offers in one place
  • Campaign prices with a start and an end
  • A delivery cut-off date ("order by the 20th to get it in time")
  • A message to past customers

Doing it without a designer

Ceylumen Commerce has flash sales with a countdown and prices that go back by themselves when the time ends. It also has 17 ready-made campaign templates, each with its colours, decoration and wording done: you set the dates once and the campaign switches on and off by itself. Campaign templates are part of the one-time licence and the hosted Marketplace plan.

The short version

Keep a flash sale small, honest and short, and end it on time. Start festival campaigns weeks ahead, tell your existing customers first, and let the shop switch prices on and off so nothing is forgotten.

More guides