I love to have a house full of flowers but it can be very expensive. What I tend to do is buy some from the supermarket and some from the local florist.
At present Sweet William, Sweet Peas and Cornflowers are in the supermarkets all of which are reasonably priced. Roses are available all year round. I tend to create mixed vases as the flowers tend to go further and they make for more interesting arrangements.
I put any small secondary stems that I remove into vintage bottles and pots so there is no waste. I use containers from Phoenix on Golborne one of my favourite shops.