This is one that I use in the office - $12 on Amazon. The only thing is that this is a micro USB plug and not USB-C, not sure how much you care for that. The angle is perfect for how I sit at work:

https://www.amazon.com/Wireless-Charger-Yootech-Charging-Included/dp/B071CFG23W/ref=sr_1_7?s=wireless&ie=UTF8&qid=1529520589&sr=1-7&keywords=yootech+wireless+charger&dpID=41uyvi66GYL&preST=_SY300_QL70_&dpSrc=srch

If you don't care whether the phone's propped up or not, this is a slightly less expensive model. It also runs on micro USB, but it's less than $10. I use this on the bedside because the charging LED indicator turns off after 10 seconds, whereas some wireless chargers have LEDs that do not turn off and ends up lighting the entire room.

https://www.amazon.com/Yootech-Wireless-Charger-Charging-Sleep-friendly/dp/B076MRKLP7/ref=sr_1_6?s=wireless&ie=UTF8&qid=1529520589&sr=1-6&keywords=yootech+wireless+charger&dpID=41bRIK0N2YL&preST=_SY300_QL70_&dpSrc=srch