Plants for a small pond

[davholla]

There are some plants I would like to get from my pond that I can not buy from a local garden center.
For example Amphibious Bistort Bareroot (Persicaria Amphibia)
There are quite big diferences in prices between 2 suppliers
£1.8
https://www.naturescape.co.uk/product/amphibious-bistort/
or
£3.95
http://www.watergardenplants.co.uk/epages/es749775.sf/en_GB/?ObjectID=68451342

I can not see any difference, any recommendations about which supplier to choose?

[davholla]