Copperhead:
Note that you'll be paying street price for foci unless you have a suitable id and a license. (And will be paying street for anything illegal regardless)
Keep in mind that sustained spells leave you vulnerable to astral attack and also prevent you from going through wards. Something else to keep in mind is the option of initiation - a boost to your magic helps quite a few things... (While initiation isn't part of the base book, I'm happy with individual initiation and could be open to initiation groups as it adds more toys to use to make character lives 'interesting' :>)
Maybe I'll just buy a Force 2 and Force 1 sustaining focus then. Then they will both be legal foci. I should be able to negotiate down to a price I can afford even if I need to buy street price. I have a good 3/3 shaman contact, Negotiation(Bargain) 5, Etiquette 5, and Intelligence 6. All things that help to get good deals if I am reading the handbook correctly. On that note, if anyone needs anything, I might have a useful contact I could reach out to.
Could you explain what Initiation is? I am not familiar with it. Or is there a good place for me to read about it?