In this case, Uber is offering a set monetary reward for every rider or driver referred, as well as the opportunity to earn awards for referring more people. Uber can’t get away with simply thanking its participants. It needs a structured program for tracking when referrals occur, whether or not they’re successful (according to the program’s terms and conditions), and issuing the promised rewards.
Tripods range tremendously in price, and the quality of your tripod should depend on the level of camera and lens you have. If you’re shooting with your phone, you can get by with a table mount like the Arkon Tripod Mount or a full-size tripod like the Acuvar 50” Aluminum Tripod. For a DSLR, Manfrotto makes a variety of trustworthy tripods starting with the Manfrotto BeFree and increasing in quality and price from there.