Something collectable is the kind of thing people buy and keep as part of a set — old stamps, toys, coins, limited pictures — often because they like it, and sometimes because they hope it will be worth more later. Shops and auction sites love the word. You can also call the object itself a collectable. Though actually, collectable and collectible mean the same thing; American writing uses -ible more often, British writing uses -able more often, but both appear. And it does not mean “you can pick this parcel up from the shop.” That is ready for collection.