90% of startups will eagerly give you a free tshirt just for asking. They love the free marketing. No need to do stuff like submit builds, etc. I have gotten free stuff from: - IFTTT (socks) - MixPanel - CloudFlare - Elastic - infochimp - pingdom - moz - rethinkdb
Lemme just pull up that poorly sitting abhorrent short sleeved Microsoft Office business shirt real quick and we are off.