I have done this a few times, The basic method is leaving a litre of green beer in the FV and swirling it around for a bit and pouting it into a big jug and thencee into 250ml PET bottles (cheap lemonade). These live in the fridge and you might get 6-10 bottles.
I am now on a third generation in the fridge and I don't like the lack of flocculation, so have started a new pack of US 05, which I will use going forward. I may keep one or two of the 3rd generation bottles for a bit longer.
This way you can get realistically 12- 15 brews from this approach without going down to generation 3, which is very noticeably less flocculant. As clear beer is something of an obsession (and I have had several of these over the years) at the current time, I only might go down 2 generations, but get 12 brews from a single sachet.
US 05 gives me the style of clean tasting beer I seem to like, although it does have unusual characteristics.
I may add that I don't think I have chucked a single sachet of Muntons or Coopers etc yeast since I re-started in Sept 2013. This is going to have to change, as there is a distinct lack of space.