Hey there Chris. I offer this service at
www.flyerservices.co.uk so I'll throw some advice up on here for you.
Leaflet/flyer marketing works great but unfortunately 90% of leaflets I see do almost everything wrong. No attention grabbing headline, poor design, no benefit-driven sales copy etc. I'm sure you've seen the kind of leaflets for businesses like plumbers which say 'this is my business name, this is what I do, this is my number'.
Because of this they get a very poor response rate. However, with the right design, right sales copy and good, trustworthy distribution, you can get a fantastic response. Of course, the percentage response you get depends on the service you're offering but I have yet to see a correctly designed leaflet not make back it's cost and a significant amount of extra profit.