The Prophet ﷺ forbade two kinds of sale and two ways of wearing a garment. He forbade that any of you sit with his knees drawn up wrapped in a single garment with nothing covering his private parts, and that a man drape himself in his waist-wrapper when he prays unless he crosses its two ends over his shoulders. He also forbade concluding a sale merely by touching the goods, and bidding up a price with no intention of buying.
وقال نهى عن بيعتين ولبستين أن يحتبي أحدكم في الثوب الواحد ليس على فرجه منه شيء وأن يشتمل في إزاره إذا ما صلى إلا أن يخالف بين طرفيه على عاتقه ونهى عن اللمس والنجش
This is a sahih hadith. Bukhari reported it (vol. 1, p. 103) from Araj from Abu Hurairah, Al-Shaab edition. Bukhari also reported it in the Book of Clothing and the Book of Trade from Ismail. Muslim reported it in the Book of Prayer and the Book of Trade from Yahya bin Yahya. Tirmidhi reported it in the Book of Clothing from Qutayba. Nasai reported it in the Book of Trade from Muhammad bin Musaffa and from Muhammad bin Salama and Harith bin Miskin. Imam Malik reported it in Muwatta, in the Book of Jami, from Abu Zinad. Abu Dawud reported it in the Book of Clothing from Uthman bin Abu Shayba. Ibn Majah reported it in the Book of Clothing, the Book of Commerce, and the Book of Prayer from Abu Bakr.