Buy and drink the sodas. Ask your friends to save theirs. It adds up fast. I acquired over 7,000 tabs in a week once, just by asking a half a dozen people to contribute. They pitched in, some of their friends pitched in, etc. Post a note in the breakroom/lunchroom at school or work, near the recycling bin. Put a bag or cup there and people might just drop their tabs in it for you. Just keep in mind that sometimes people collect these for charities, often a drive to purchase a wheelchair for someone who needs it. Find out if that's going on, and if it is... don't interfere. Let them have any tabs you collect. Wheelchairs are expensive.