Depending on your age find someone over 18 you trust to take you out and buy you a piece "for tobacco". Otherwise if you register the gift card online then use amazon. You can usually find a bubbler or pipe for under $30 that is prime eligible.

Pipe on amazon:

https://www.amazon.com/Bungleweediouse-4-5-incense-holder-Crush/dp/B01M628B38/ref=sr_1_1?ie=UTF8&qid=1478053535&sr=8-1&keywords=mc+pro

Bubbler on amazon:

https://www.amazon.com/Bubbler-4-5-Inch-Paraphernalia-variety-Designs/dp/B01KQT83M6/ref=sr_1_2?ie=UTF8&qid=1478053706&sr=8-2&keywords=bubbler&refinements=p_85%3A2470955011