Carphone Warehouse sold 14,000 Alcatel OT 203 handsets in the first two hours of trading, and shifted 47,000 units over a three-day period.
Carphone said the handset is the fastest selling prepay device in its history.
The OT 203, which is on Orange prepay, was part of a promotion Carphone launched in partnership with The Sun newspaper priced at £9.50 with £10 free credit. It went on sale on October 14 and was available to customers who collected four tokens from the newspaper.
Carphone said it expects the handset will be the number one selling prepay phone for the week.
Carphone chief executive Andrew Harrison said: “The speed at which this handset flew out of our stores was simply staggering.
“We saw an extra 100,000 customers over the three days the promotion ran, which just goes to prove that customers still love brilliant value handsets.
We shouldn’t forget that for every customer who wants an iPhone there is another customer looking for the best value on the high street.”