Question
I intend to buy some organic topsoil.  If I buy too much, can I save it for next year and future years ?  Do I need to protect it ?  Is it a good idea to buy it in bulk ?  And is organic top soil as good as compost manure ?  The seller says that it works as well as the manure.  Thanks !

Answer
Hi Neil, I'm a little curious about the "organic topsoil".  Did the seller make it?  From what?
Soil is made naturally from decomposing organic matter, plus inorganic minerals.  All this stuff is processed by worms, nematodes, bacteria and fungus to make topsoil.
If what he's selling is a blend of bark/sand/leafmold/clay, then it's not topsoil, but it is a soil mix that you could grow plants in.  If you keep a pile in your yard, I'd keep it covered to keep it dry.  It will be easier to work with and it will not decompose as quickly.
Composted manure is a good soil amendment.  If it's composted, it has little nutritional value, it is excellent texture for the soil, but it is not something to be used by itself to grow plants.
Bulk products are usually cheaper but you do run the risk of introducing more weed seed.
If you are improving existing soil, then either product may work fine.  Do not remove old soil and replace with new soil, always blend the two together. If you are building an elevated bed, then a soil mix is what you need.
Jim