The definition of compliant is obeying. An example of compliant used as an adjective is a compliant student which means a student who follows all of the rules. complying or tending to comply; yielding; submissive.
We're having the ring bearer wear a tux that is age appropriate. It costs about $70, everything included. Your tux shop should have these or be able to order them. Edited to add: A friend several years ago had a ring bearer in her wedding and dressed him in a shirt and tie instead of a tux.
According to The Knot, new tuxedos typically cost between $300 and $500 to buy, and renting a tux costs 10 percent to 30 percent of this price. As such, you can expect to pay between $30 and $150 to rent your tux.