Where to buy Topiary, in the United Kingdom
Your local garden centre will probably have at least some items in Box, usually ball or pyramid shapes. The people having a heart attack at the price are those who do not realise that the plant is probably already five to ten years old and represents a considerable investment on the part of the nursery. Large, ornate topiaries usually run into hundreds of pounds and, strangely, people tend to laugh at these prices rather than have heart attacks.
So, Rule One is buy small from a nursery and create your own unless you require just one or two instant specimens. In this way plants will acclimatise to your conditions and you can have any shape you want!