Buying and selling online safely: a checklist for buyers and sellers

Online marketplaces make it possible to buy almost anything from almost anyone. That convenience depends on trust: buyers need to know they will receive what they paid for, and sellers need to know they will be paid for what they send.

Most problems in online trading can be avoided with a few simple habits. This checklist covers the most important ones for both sides of a sale.

For buyers

Read the whole listing

Photos show what an item looks like; the description tells you what you are actually buying. Check the condition, size, model, what is included in the box and whether the item is new or used. If something important is missing from the description, ask the seller before you buy.

Check the seller

Look at the seller's ratings, reviews and how long they have been selling. A long history of positive feedback is a good sign. Be more careful with brand-new accounts selling expensive items, and read negative reviews to see how the seller responded to problems.

Be wary of prices that look too good to be true

A brand-new phone at half the usual price is rarely a bargain. Unrealistically low prices are one of the most common signs of a scam or a counterfeit product. Compare the price with other listings for the same item before you decide.

Keep communication and payment on the platform

Scammers often ask buyers to continue the conversation on another messaging app or to pay by direct bank transfer "to avoid fees". Moving off the platform usually means losing any protection it offers. Keep messages and payments where there is a record of them.

Protect your personal information

A seller needs your delivery address and contact number, not your passwords, one-time codes or full card details sent by message. No genuine seller or marketplace will ask you to share a verification code.

Inspect your order on arrival

When a parcel arrives, check it as soon as possible and keep the packaging until you are sure everything is correct. If there is a problem, contact the seller promptly and politely, with photos. Most issues are resolved quickly when both sides communicate clearly.

For sellers

Write honest, detailed listings

Clear listings prevent disputes. Use your own photos taken in good light, show any defects, and describe the item accurately: condition, dimensions, model and what is included. It is always better to under-promise and let the buyer be pleasantly surprised.

Price with the full cost in mind

Before setting a price, add up the cost of the item, packaging, delivery and any platform fees. Check what similar items sell for so your price is competitive without selling at a loss.

Reply quickly and professionally

Fast, friendly answers build trust and lead to more sales. If a buyer asks a question, the answer may help other buyers too, so consider adding it to the listing.

Pack carefully and share tracking

Most damage happens in transit. Use sturdy packaging, protect fragile items and share tracking details with the buyer when possible. A well-packed parcel tells the buyer they are dealing with a careful seller.

Handle problems calmly

Sometimes things go wrong: a delivery is late, an item is damaged or a buyer changes their mind. Respond calmly, explain what you can do and keep a written record of the conversation. The way you handle a problem often matters more to your reputation than the problem itself.

Watch for common seller scams

Sellers are targeted too. Be cautious of buyers who claim to have overpaid and ask for a refund of the difference, who send screenshots instead of real payments, or who ask you to ship before payment has cleared. Confirm that payment has actually been received before you send anything.

Trust is built by both sides

A marketplace works when buyers and sellers can trade with confidence. Honest listings, clear communication and a few careful habits protect everyone and make each sale a little easier than the last.

SUM THINGS is built around that trust: an online marketplace where people and businesses can buy and sell with confidence. If you would like to sell on SUM THINGS or have questions about the marketplace, write to us at info@sum.lk.