Analyze the prices of competitors offering similar products or services. Then set you prices near their prices. This will mean your prices are always near the market price.

Alternatively, you could also determine what it costs to produce your good/service and charge a set percentage over top of costs. For example, if you want a 30% profit and it cost you $1 to produce your thing, you would charge $1.30. This method can allow you to seriously undercut your competition.