I've never seen Pride of Nations sold for $1.50, but I haven't been watching the price, either. I came pretty close on Jan 2, 2012 when I picked it up for $1.70.
I had already purchased ACW and BoA2 from Matrix. I hadn't planned to buy this game, but I loved my other AGEOD games so much I bought it. I couldn't pass it up for that price.
I've played the game a lot and I think it's probably worth $25. I think it's a lot more complex that ACW and BoA2.
My goal is to buy games at less that what I think it's worth. I have failed many times, but try to wait until Christmas sales. I'm kind of a cheapskate.
This low price is probably the result of yet another GamersGate screw-up; this is the company that is infamous for accidentally stacking discounts (first 70% off, and then another 70% off for good measure), at one point resulting in them accidentally selling a $300 Bethesda Softworks collection for $30 (90% off!), which included a couple of titles that at that time retailed for more than $30 each, even when on sale! That did not end well.