Apple (AAPL) and Samsung (005930:KS) built big tablet businesses by appealing to early adopters with money to burn. Lenovo (992:HK) and other companies are working on sub-$100 tablets aimed at the lower end of the market. But starting next year it may be tough to compete on price with the Aakash 4, a 7-inch Android tablet developed by British manufacturer Datawind and India’s Ministry of Human Resources Development. Datawind Chief Executive Officer Suneet Tuli said at a Wired conference in October that the device has twice the processing power and RAM of the first iPad and will cost as little as $40. The company, which has shipped about 1 million of its earlier models, will make its money on app sales and ads, he said. Now the No. 2 tablet maker in India, Datawind plans to start selling in the U.K. in the next couple of months.