Think I sold a set of Hat Napoleonic Swedish Infantry too that went for more than I originally paid. Didnt hang on to them as I wasnt a fan of the style of them...or the plastic.
They didnt sell anywhere near what the Zvezda Hussars did, but think it was still at least double.
I searched high and low for the original dismounted Boers that Strelets released and kept drawing a blank, luckily they re-released them and I snapped them up. A few years ago I promised myself to buy stuff when it came out even if I had no immediate plans for it but the flood of sets was so vast that I couldn't afford to. Don't generally think about the later value of sets, except I did put aside a box each of Orion's Boxers and Vikings with the bonus figures which are mint in box. Not that I've looked to see if they are in demand or not.
I dont buy sets with the thought of what they will be worth later either. I buy them for one purpose.....to use them!!! Im not a collector per say. Instead I paint them up ready for when I build a diorama.
I just got lucky on ebay. Had some sets that didnt really need, so rather than let them collect dust I put them on there thinking somebody might want them.....and boy they sure did!!!