The last time I saw a mainstream dept store with tons of lingerie was J C Penney, in Salem, New Hampshire, in 2000. I bought a couple of shortie half slips in black and white and sometimes wear one over panties, under my jeans - or lift it up over my bust to wear as a chemise/shemmy (but only for a few minutes for fun.
The runner up was a Sears store in Kingston Ontario, circa 2007, which gave me a few quivers and a couple of purchases. However, I was with a girl who was less supportive than the one I'd been with in Salem.
As to whether my partners wore or wear frillies, I find that it's relatively easy to persuade a female friend to wear stayups than it is to induce her to wear garter belts or girdles with straps, although have had more success with corsets
There's tons of frilly lingerie at EBay and elsewhere online - beautiful retro stuff for those of us who might like to dress as prairie wives. However, there are always pitfalls to buying online, unless it's a known and trusted source. Hope this isn't too far off-topic