Most brick and mortar retail stores carry "mounted" rubber stamps. These usually come with the foam pad and the pink rubber stamp adhered to a piece of oak called a block. They will have the stamped image on the outside of the block for easy recognition. This type of rubber stamp is the most convenient and hassle free way to buy rubber stamps.
These types of rubber stamps are more expensive and when you accumulate a lot of them, they become very hard to store unless you are lucky enough to have a room dedicated to them. Online stores and shops will also offer "unmounted"stamps as well as "mounted." When you purchase these types of stamps, you will only receive the pink rubber stamp that is not trimmed, put on a cushion, or have a block. You will have to purchase some kind of mounting system. You will need special scissors to cut the stamps out and trim them, and then you need acrylic blocks and a storage system.
It sounds like so much extra work, time, and money right? There is a big advantage to buying theses "unmounted" stamps. Once you have initially bought the above tools, you will only need to buy foam cushion and cling pages for storage. The best thing about them is that they are about half the price of the "mounted"ones.
Another great advantage is it takes just a little space to store them in. I bought a 5" binder and bought cling sheets. The stamps stick to the cling sheets and you can make a stamped reference on the opposite side so you can identify them quickly. As your inventory increases, you add more binders, and cling pages. Soon you will have enough stamps to put into categories or different colored binders.
I have well over one thousand stamps and I can't imagine them all mounted to blocks of wood that have to be stored somewhere. If you shop around and do your home work, you can find the items you need to mount your stamps with on sale at different times of the year. Buy binders during back to school sales, sign up for sale notifications at you favorite online store, and don't be afraid to shop the bargain bins.
I know I have given you a lot of information based on my experience and now it is up to you to decide how to buy your rubber stamps. There is no right way or wrong way, it depends entirely on your needs, your time, and your finances. To those who stamp to make a few cards or scrapbook pages, you may want to buy only "mounted" stamps that you can store in shoe boxes. Those of us who do stamping on a regular basis may choose to invest in "unmounted" rubber stamps and all the accessories. It doesn't matter whether you choose "mounted" or "unmounted" rubber stamps as long as they perform adequately for your stamping project with minimal stress and frustration.