While ideally one would want to test an app on all phone models before releasing, I currently have the budget to buy just 1 WP8 to test my app on. But before shelling out a few hundred bucks, I thought it would be wise to check if there is such a thing as a certain WP8 model best suited for software development. And by that I mean that if an app runs well on that specific model, then there is a high probability that its runs fine on all other WP8 models out there.
If you’re looking for a lower-spec device, the Lumia 520 is currently the lowest spec WP8 phone, and most likely the cheapest too. That’ll give you a good idea how your game will perform on basic hardware.
The main thing to test with the higher spec hardware is how your game adapts to higher screen resolutions, but you can easily test that in the WP emulator, which offers a variety of different resolutions.
Having said that, does anyone have any benchmarks for how the really high res devices like the Lumia 1520 perform? I’m assuming that they outperform the Lumia 520 but I’ve not tried one myself so I can’t be sure.
A 520 should cost about $70. If it runs on that it should run on everything.
Do you know dvlup.com? If you’re already in development, submit your apps there. The 520 isn’t very expensive (measured in points, which you get for completing challenges)
Definitely buy a bottom-end device - a 520 or a 625. I recently got caught out: having spent six months working on a 820 developer device, I found that what I had built did not perform well on the low-end devices, requiring some pretty heft refactoring. So go for a low-end device, and use the emulators to test things like high-resolution displays.
Thanks to all. I got a 520 
Thats not really true as some phones can have other issues like I had with my app. But for trying on real device, 520 is probably best because of lowest performance and still very high popularity (about 30%). But also wp80/81 emulators are very good in term of emualtion and I encourage to try ALL of them for testing until app will run correctly on all of them.
True. Devices like Lumia 1520 are said to have resolution issues…
I had problems with net communication too early after creating game on some higher devices (not on 520) - and surprisingly same strange behavior on some emulators! Previously I did not pay much attention to different emus, only tested on one I picked up firstly, others often crashed because I had low free space on my ssd :D. This way I realized it’s very good idea to test app on all of them :).