https://www.amazon.com/WICAREYO-Protector-Plastic-Protective-Display/dp/B09ZP8M5N4?th=1 - 10pcs for $18, with a host of other options on there. Some with UV protection if you’re showing them on a shelf or display exposed to sunlight.

If my figures were still carded I’d have put them in there. Looks pretty cool on the shelf on a few collector videos I’ve seen.

As for valuation I’ve no idea, https://rebelscum.com is still around, and has some guide prices, and their own forum.

I’m still amazed that good Kenner ships and sets from our childhood era is cheaper than the new LEOG sets and ships!