Yes I must admit I'm with bearleigh to a certain extent because buying from the local nursery keeps the local economy and community going also.
That said, poundland and lidl often have very good plant bargains.
Crocus is more expensive than elsewhere and the exact same stuff can be found cheaper if you look on
primrose
which will also often give you a price comparison if you type in a plant name.
Also, it stops the local nursery form becoming an internet ghost. This is what has happened to Jaques armand which used to have the most amazing selection of bulbs and still has a good selection online and shows at shows but the reality of the nursery is that half the land has now been sold off and the bulbs are no longer stocked locally but in some internet warehouse somewhere.
Like anything, waiting a bit will often bring the price down, for example Sarah Raven is selling her dahlia tubers 30% off which is a brilliant bargain as its certainly not too late to plant them out and her tubers are fantastic.