Unlocked Huawei E5775 mobile WiFi router can be purchased in USA with a price US $210 through e-commerce online website eBay. In another places you can also get its variant model, E5775s-925.
3G DC-HSPA+/HSPA+/HSPA/UMTS/WCDMA Bands 2100/1900/900/850Mhz and 2G GPRS/GSM/EDGE 850/900/1800/1900 MHz network bands.
In 4G LTE network, E5775 is capable to download a file with maximum speed up to 150Mbps and upload speed limit is up to 50Mbps. It has two antenna ports (you need to purchase separately) to get better network. It is compatible with Windows, Linux and Mac OS.
If you purchased locked Huawei E5775 MiFi WiFi router to EE (UK), Telestra (Australia) or any another countries carrier; then you can not use another network provider SIM in it. To be able to use with another network provider SIM, you need correct NCK code / Unlock Code / Password, which is not free.
For unlocking guides and unlock code refer this article.