620 - my first WP, got it February 2013. 220 euros from Vodafone Germany.
ATIV S - upgraded to this three months later for 254 euros. Sold the 620 on eBay.
520 - bought this in the US for $50 (AT&T). Cost nearly as much to unlock it.
730 - got tired of waiting for ATIV S ROM upgrades, needed dual-SIM phone (179 euros at MediaMarkt Germany)
530 - Impulse buy at Saturn, 59 euros. Gave to wife in hope she would develop interest for WP; hasn't happened yet, she uses for two less-used SIMs.
532 - Another impulse buy, this time at Aldi for 69 euros. Gave to daughter, who mostly plays games on it, but also has two SIMs.
640 DS LTE - Dropped my 730 and smashed the screen, needed another dual-SIM. 154 euros on Amazon.de. Superb value and a nice sidegrade, but would have bought something fancier if available, but found the Lumia 550 too expensive. Ended up getting the 730 repaired too. I have lots of SIMs.