If your gonna order loads of parts, work out what you want, check various prices around, then email one place and try and get a good deal for buying all from them.
A couple of points to remember...
1. You should get a better price if your buying quite a bit of kit together.
2. Freight costs should be cheaper overall for sending all together (as apposed to separately).
3. Expect customs to add 10% or so to what ever you pay (for international anyway, greenline, nengun, rhd japan etc)