In general buying an existing business is less riskier than starting from scratch. However, if not properly researched - this can turn out to be more costly. A prudent investigation needs to be performed before buying a business. Understanding the sellers motivation for selling and how profits are generated is important. Profits can often be manufactured.
Free cash flows are the true identifier of value and wealth creation. If there is a small true cash profit and it only allows the owner an average salary - it would not be wise to merely 'purchase a job'.
When purchasing a business, you want an independent valuation, unemotional and with zero reference to the sellers asking price.