The first that comes to my mind is the Schiit Mani phono pre. I still have it boxed as an emergency back-up, too inexpensive to sell and then be without should I need it.
Besides that? My two B&K amps I bought used. Great bargain, and sound great. Still have one in my bedroom system
And not necessarily ‘cheap’ for their day, more mid-fi by todays standards, but I really liked my Polk 5 Jr speakers bought in the early 80’s. Still have them, not in use, but keep them as they have a sentimental value.