Wow. I found all of my Corningware in thrift stores for a whole lot less than what this seller is charging, and continue to see pieces for under $10. I've never paid more than that for any of my stuff. I'm guessing he/she looked on eBay before deciding on how much to ask for the various pieces. I also pick up the detachable handles for use on stove tops whenever I see them. Nobody knows what they are, so a buck or two is usually all they cost.
Without the specific item numbers, it's hard to know if some of these would fit on the vintage tea light warmers/servers. I have a Trefoil piece that I use on one of those warmers, and I don't think I paid even $5 for it.