Roadie’s Terms and Conditions specifically prohibit a driver from soliciting tips or additional compensation from Gig recipients or Senders. Senders are given the ability to add a little extra to a Gig if they so choose, but they are not expected to pay anything outside of the price Roadie gives them.
Keep in mind that if a Gig doesn’t seem worth it, you are totally free to pass on it and wait for one that fits your plans and pays what you want. The pricing of each Gig varies, so while one may not work for you, another one may be the perfect fit. Drivers aren’t required to take a certain number or percentage of Gigs, so there's no harm in waiting for the right one!