Buying customers in any business is a common thing. Investing money in advertising, you thereby buy customers. If you invested $ 100 in advertising, 10 customers came to you, and the net profit was $10 and you are in the black, then you should continue to buy customers through this advertising channel. But in addition to the profit you get customers and can further interact with them, sell them something else, make special offers and so on.
In some countries like the US, some companies buy customers even in the negative, not once I have seen such offers in the market of traffic arbitration and CPA networks. Typically, these companies buy customers in the negative, because they are very well set up sales, and they know the value of the client for their company.
Today I saw 2 identical banners, one hung on the building of the shopping center, and the second a little far away on the wall of the neighboring building. Most likely the placement of both banner costs the store owner on a monthly basis in any amount. But there were no special codes or offers on these banners. They do not track the effectiveness of this advertising and merge the budget that could be directed to the purchase of customers. Therefore, it is always important to consider all the performance indicators of each individual tool and advertising channel. Do you want effective advertising and effective buying customers for your business? Then consider the performance indicators and know the purchase price of your customer.