Mock up - Photoshop - two prices

I am a web design company looking for someone to do the best photoshop mock ups. I need: 1) One price if the client doesn't accept your file. 2) Another price if the client accepts the file and you email me the PSD. (we would convert to html ourselves and not need html/css - just the psd. ) Each project has competing designers - so even if your good we wouldnt accept your file all the time because they might choose the other designers design. I need to see your prior work. If you offering a free mock up - let me know. The problem with offering me free mock ups is that your always competing with other designers and might not want to waste your time. - and I might only need psd and not html/css coding of your psd.