The HughesNet WiFi Booster itself doesn't use any data. What it does is extend the range of the existing WiFi from the HT2000W modem, so any data that you would normally use via WiFi would still be the same while using the WiFi booster.
In reality, though, it could actually help to save you a little data, but that all depends on whether you were using more data than normal due to a weak WiFi connection that caused dropped data packets. If that was happening, you may see a small benefit, data wise.
Hope this helps.
AMD FX-6100 | Samsung 250GB 840 EVO SSD | Western Digital Blue 500GB HDD | 16GB DDR3-1866 | EVGA Geforce GTX 550ti | Windows 10 Pro 64-bit