You might want to try mail order. I ordered a half dozen Mahonia aquifolium from Burnt Ridge Nursery (Onalaska, WA) a few years ago. They were about 2-2.5' tall and were about $6 each. They ship bareroot, which saves on shipping costs but is not that great for the plant. Mine took a while to get over the transplant shock, but are doing fine now. The stock quality of my order was decent.

Thanks for the advice.

Ubiquitous at independent outlets here - although under garden center conditions in particular often partly defoliated by rust, which seems to have become universal on it. You might consider this before making a special effort to get and plant it.