Frankly, you have invested time and money into creating your product. What price would you put on your loss of trust and credibility with your customers if you release a product with many bugs? This is even more relevant when your product deals with sensitive information such as personal data and credit card information. If you are dealing with some sensitive information, there may be fines and penalties associated with breaches.
So you know you need testing, but can you afford it? For a fraction of the cost of hiring your own testers, you can often use the independence, creativity, and efficiency of an outside team of software testers. Use them when you need them. And while no product is problem free, you will have the confidence that you are releasing the best quality product you can.