Also, when you opened the bottom, partially decomposed materials may fall out along with the finished compost. I heard of one woman who built a compost bin out of a discarded rabbit hutch. She set it up on cinder blocks at each corner and placed a metal tray underneath the bin and between the blocks. She just slid the tray out to access her compost, then returned the tray to its location. Ability to turn pile.
Some commercial bins have a handle to turn the entire bin without having to handle the product.
Ask if the vendor has a demo bin FULL of materials you can test. Make sure the full bin is not too heavy for you to turn. If you are going to place the bin where you or your neighbors will see it, you need to make sure its appearance is not objectionable. Materials can be located almost everywhere and are available at any time of the year. Assuming that the finished compost is going to be used on your property, the best place to find the raw materials is on your property.