I have fresh flowers pretty much all the time in my house. I buy them usually from the flower markets or sometimes regular markets so they are definitely fresh to start with. Having said that, supermarket prices are often so cheap that it is worth getting but I never, ever buy ready made bunches from any of these places.
I buy 2 or sometimes 3 different types of flowers and arrange them myself. For instance, buying white lilies (oriental, I think) completely in bud, will last for weeks. If you add a bunch of some filler flower which is inexpensive, it looks good right from the start.
Generally speaking, I look for types that last well in a vase. I do however, lash out for the short time in Spring that both iceland poppies are available despite their short livedness (tip, don’t buy open flowers) and also sweet peas.
I used to have a big, country garden but now have a small inner city one. My husband regularly cycles to the markets and buys them for me. He reckons he gets enough brownie points to last until the next weekend!