You may want to rethink that a bit for your project.....yes you can get good prices online, but you can't always get things as quickly as you need them, or if something crops up or understand all the alternative, which takes time if your hands on with the project "doing".
We've established relationships locally (we would like money to stay in local area if we can) been straight and told them that, but also that we are looking for a "sensible" cost, and made no bones about that fact that we do check prices online. So far, its worked for us, and when there has been a need for a quick response they've come up trumps.
Also set up accounts, if nothing else it helps cashflow.