Most commonly, a cash deal comes to play when someone offers to do the work for the least amount of money. They ask for cash, and nothing gets written down in the process. The business that does cash transactions will not claim the income and ultimately avoid paying taxes altogether. This process is illegal, and most likely the business won’t have the proper insurance and a legal business licence as well.
Even though that a cash deal may be the cheapest quote, a cash deal means that there is no paper trail if legal issues arise. There will be no receipts, no contract in place, and almost guaranteed no warranty on the work completed. With no proof of payment, there is no way to hold the home contractor accountable for the work that he promised would be completed on your home.