They make ziploc type baggies from 1x1 inch on up. The companies that sell them usually do so in 1000 or 10,000 sized lots. A bit much for most of us. But at many flea markets there is usually someone that sells them in smaller lots. Normally for only a couple of bucks.

Another Idea is to use straws. But that depends upon the the pill size. Fold the ends and glue shut.

How to do this can be found at Packets