Everyone shops around for the best prices, sure folk do it on here for the best prices for different materials & products, so I would expect it from customers also. Every job / customer is different so I take each job as it comes. One thing I do do though, Is after I've got the job and I'm getting to know the customer, I always ask if they had other quotes, how they chose me, why etc. Its good for feedback & customers are always happy to explain why they chose me. Usually it turns out my prices were about the same, rarely the cheaper or sometimes the most expensive.. but the feedback helps going into future quotes, 'cos its not always about the price (sometimes!)