The value of the discount coupons for digital-TV equipment should be nearly halved from 1,000 baht, says the Foundation for Consumers.
A price of 512 baht would more accurately reflect the real cost of the equipment and reduce the financial burden on the state, said Saree Ongsomwang, the foundation's secretary-general.
Citing a survey it undertook, the foundation said a set-top box costs $13 (421 baht) in the United States while one fitted with an antenna sells for $3 more or 518 baht.
To promote the transition to digital TV, the National Broadcastiong and Telecommunications Commission (NBTC) intends to mail discount coupons to all 22 million households in the country.
The subsidy will come from an NBTC fund that gets its money from spectrum auctions, administrative fines and licensees' mandatory contributions.
The tentative value of the coupon was set at 1,000 baht, costing the fund 22 billion baht. The amount may be changed pending a review.
The NBTC, meanwhile, is also warning consumers against scams, saying it has never appointed anyone to supply set-top boxes on its behalf.
Some consumers have reported being approached by companies claiming to be NBTC distributors. They promise to supply boxes to people's homes without them having to wait for coupons.
The NBTC said consumers looking to buy equipment and TV sets should look for its Class A Broadcast hologram mark and its "Doodee" sticker.
The NBTC has also posted a list of approved equipment online.