Nokias had a rough time with its high-end Windows Phones over the years, but its excelled with its cheaper handsets that cater to emerging markets and anyone interested in a budget smartphone. Announced today at Build, the Lumia 630 and 635 focus on expanding the latter category. The new devices come with Windows Phone 8.1 onboard, and while the 635 includes speedy LTE data, the 3G-only 630 will also come in a dual-SIM variant.