I'm always raiding the Plant Rescue stand at garden centres and have had quite a lot of luck.It's a very cost-effective way to buy perennials, which should come up the following year with a bit of TLC. A few years ago I bought a Brunnera "Jack Frost" which was close to death in Homebase and I have divided it several times since - the silvery leaves look fantastic pretty much all year round. People are always asking me what it is. On another rescue mission, I saved a wonderful Astrantia with variegated leaves which is stunning - the flowers are pretty but the leaves look like they have been dipped in white paint. (Sounds horrible but looks great next to purple heuchera leaves). I took a bit of a leap of faith in spring, buying what looked like a pot of soil. The label promised me a Solomon's Seal and I could see healthy roots in the compost. I planted it and it has romped away. And this summer I bought a rather crowded Veronica which had gone over, but hopefully will give me lovely white flowers next summer. I divided it into three and it looks like I may need to divide them again before I plant them out this Autumn. So, not just one plant for half the price, but possibly six or more!
We have to be patient, we canny money-saving plant rescuers, but it sure is worth it. I'm sure I have saved hundreds of pounds over the years, as it really is only worth growing perennials in my shady garden and they can be very expensive