Hi hun!! You should be able to start on the diet pretty quickly! I went to my chemist and she weighed me, took all my health details etc etc and gave me the shakes! She gave me the dvd lipotrim recommend watching at the same time but just said watch it when i got in and return it the following week. I know some other chemists insist on you watching this before they give you the shakes and then some others dont make you watch it at all! So that really just depends on who you go to.
Buying wise, you should only have to buy your shakes and a shaker to make them in if you need to. I know a lot of people on here use a blender to mix them but i've always used the shaker and i think they are about £5 each thats all!
I went as early as i possibly could to my chemist to get weighed so that i knew every week i would be able to go and have it done at the same time, without having drank any of the vast amount of water you have to try and drink lol. Every little bit of extra weight counts when you get on those scales. So maybe you could try and do the same. However, for your first weigh in i shouldn't think it matters too much! Just getting started is the main thing!
Hope that helps a little!xxx