I've a 170ft back garden (don't know width but width of a semi-d average house). I'd a gardener do up design for me which roughly covered removal of old shrubs and trees, removal of old wonky path, new plants/trees/shrubs, brick kerbing on garden, raised brick herb bed, raised section in garden, new garden path and stepping stones. I loved the design. Unfortunately other half didn't!
Cost was 8500 (less VAT) and he was open to barganing - and some of the suggested design could be done cheaper (i.e. price included laying new lawn with truf rolls - v. costly). So all in all if I had the money, which I don't, it would have been worth it IMHO. Also he was willing to do in chunks of work, so therefore spreading the pay load for me.
HTH.