|Most of these are quite in demand these days. Some collectors opt to proudly showcase their coins in archival folders, while others like airtight capsules, or mylar-lined carboard. Whatever you choose, don't store yours in the soft flips you often find in the marketplace. These are made from polyvinyl chloride which decomposes over time and destroys the piece it was to preserve. If you buy a coin already in such a sleeve, move it as quickly as possible to something better. You might consider acetate flips, but recognize that these are hard and may scuff the coin if isn't placed and removed carefully. While they aren't airtight, they are choices for moderate priced coins that will untouched for numerous years.
One thing is certain: regardless of how you decide to keep your coins, it will forever a source of never-ending enjoyment.