you must buy cured live rock or its useless to you. you can buy it from a reefer breaking down a tank very cheaply, and you may get some live sand too. just make sure it stays wet on the journey home. i suggest you join ultimate reef
some bargains may crop up on there.
a good skimmer would be either the TMC v2 120 (£50 new) or the TMC v2 400 (£50 second hand on ebay) theyre both made by the same brand but have a slightly different design, but the 400 would do a better job of removing DOC's and proteins
errr..... well, it all depends, you can buy uncurred rock if you have time to cure it yourself - which is easy
but most people buy cured to save time - as Truck said the best thing to do is find a reefer breaking down a tank and buy their lr and sand, much cheaper, I certainly would not buy lr from a lfs
In fact you could buy everything second hand if you don't mind waiting for a bargain to come along, could be fun and I for one would enjoy hearing about your bargain finds
Seffie x