I've had loads of flyers printed over the years. My experience has been that if you create (or someone creates for you) a classy flyer with photographs on it, the cheap suppliers tend to be very poor on quality. I got 10,000 printed once, and the colours varied so much they were dreadful. Now I use a local printing firm, they're more expensive, but I insist on seeing and approving the proof before printing, and make it a condition that all the print run must be to the same quality as the proof, or they have to do it again.
Any reputable printer will be happy to agree to this. Your flyer is the first point of contact, and will set the customer's mind as to how they think of you. If the flyer is poor, they'll think you are the same.
Cheers,
Ian