White Monarchs are running around $50-$70 at the moment.
D&D v1 Set is worth around $200
Smoke and Mirrors v1 is closer to $100 than it is to $200. v1-v3 sets seem to be going for around $120-$130 on ebay lately. White Monarchs also have dropped in value lately, going around $35-$45.
The "standard" rare E decks (Red Artifice, BG1E, Gold Arcane and LTD) seem to hover around the same price. RA and LTD go for about $50, and GA and BG1E go for about $80-$100 without a ton of fluctuation in price. Sultan Treasury is hovering around $25-$30 lately.
Split Spades could also be included in this I'd say. 1st edition Lions regularly go for over $30, and the Tally Hos closer to $40. Haven't seen the Bees in a while but I'm sure the price for that is similar. Another notable deck that has been increasing in price is the T11 Blue Jaqk deck. I don't think you can find one for under 20 bucks anymore.
This is just from me ebaying quite a bit in the past 4ish months. I've been unintentionally keeping track of quite a few decks and their prices, specifically the ones mentioned in this post (also the Wynn decks, but those were covered earlier I think).