For the past four months, Ms Lilian See has been flying home from Hong Kong with items and packages meant for strangers.

These could be anything from the sought-after Apple Watch to Starbucks tumblers from Japan and Taiwan.

All were requested by buyers through Airfrov, a Singapore start-up that pairs them with frequent travellers who do not mind picking up items not sold in Singapore, and carting them back.

This way, buyers need not pay costly shipping fees while travellers can use their additional luggage space to bring items back.

Users post on Airfrov the item they want, the country where it is available, and say how much they are willing to pay for it.

Airfrov recommends that users offer a small fee to attract potential travellers to help with the purchase. Airfrov charges the buyer 7 per cent of the price agreed upon by buyer and shopper.

Travellers using Airfrov can then decide what is worth their while to pick up the item, before accepting a shopping request.

For the most part, Mrs See treated it all as a game once she learnt about it during a visit home, in March, from her base in Hong Kong. "It was a logistics game, to decide how to buy, and how to get my friends and colleagues to bring it back to Singapore," says Mrs See, 35, who works in the customer service industry.

Buyers pay the full amount when their requests are accepted, and Airfrov collects the money on the shopper's behalf and pays him once the items are delivered to Airfrov's office in Purvis Street and picked up by the buyer.

Mrs See estimates that she has earned a tidy four-figure sum for her efforts as a personal shopper, though she likens it to helping friends and family buy items whenever she travels. It also explains why she goes out of her way to help with some purchases.

Although she has moved home to Singapore, she is going to Hong Kong again to tie up loose ends. And because McDonald's Hong Kong accepted orders for the sold-out Nanoblocks sets last month, she plans to bring the final lot home for buyers at the end of this month.

Airfrov was started by Mr Cai Li and Mr Robi, both 29 and friends from junior college. Mr Cai, who travelled constantly in his previous job in the plastics industry, started getting requests to pick up items on his travels.

He roped in Mr Robi, an Indonesian-born Singapore permanent resident, who created the iOS app. Both men pumped in $10,000 to start the business.

Since its inception in January this year, Airfrov has registered more than 3,000 users and closed over 350 transactions.

Frequent travellers who complete multiple requests are given a "Verified" status, so users know these travellers are dependable.

The most common items requested are those not sold here, such as Tokyo Banana snacks from Japan and limited edition items, like the six Nanoblocks sets available at McDonald's in Hong Kong.

Most of the requests are for items sold in the United States, Japan, Hong Kong and Thailand.

Airfrov allows transactions from 40 locations and plans to expand the list, depending on user feedback. "We are definitely planning to expand to other countries, though there are a few things that we are working on to make sure we provide the best user experience," says Mr Cai.

The buying experience will be focused on Singapore for now, though some customers overseas have been using Airfrov to get their requests fulfilled.

For example, Singaporeans living overseas have requested items from travellers who happen to be headed there.

In such cases, the buyer and traveller arrange their own meet-up, and Airfrov pays the traveller when both sides indicate that the transaction is complete.

The biggest item requested, and accepted, was a massive Step2 Deluxe Canyon Road Train & Track Table set from the US. An expatriate lugged the US$80 (S$108) item, which weighs 13.5kg, back to Singapore for $150.

There is also a sense of social networking on Airfrov, as visitors to the site can duplicate a request from another buyer. This adds incentive for the traveller, who might end up bringing back multiple units.

Airfrov's founders say that so far, there have not been any disputes with payments or items delivered, although there have been instances when a traveller has been unable to complete an order, because the item was sold out.

The service is looking to launch an Android app soon.

It recently introduced a Follow and Recommendations feature for its "Verified" travellers.

Mr Cai says: "This is a prevalent behaviour that we observed. Travellers love to share unique items or great bargains that can be found only overseas. They call it 'die die must buy!'

"Hence Airfrov has also become a discovery platform for users (buyers) to find out the latest trends, or unique items that can be obtained only from overseas."