No warriors? Well, if you don't have any necrons yet, you really shouldn't do it. Most of the units listed here don't work in conjunction with the other ones listed here. I.e.the Destroyers are good for shooting, as are the Immortals, but if you use them both, you won't have much points left for the rest. Mostly, the Necron army only works well if it is cc-oriented or shooting oriented. If you, for example, have 10 Flayed Ones and 3 Wraiths in your army, and some Destroyers and Immortals, you won't have enough cc-punch to hold yourself against a cc-oriented foe (Orks, 'Nids), and you also cannot outshoot them, because you don't have enough good shooting units. So my conclusion: if you're new to the Necron army and have that amount of money to buy stuff, you'd better first get 1 or 2 battleforces, an HQ unit, and some immortals and destroyers or cc units.