The Internet has really taken off with shopping sites. There are basically
two types - ones where you buy from companies and ones where you can buy
and sell to others as well.
Ebay allows you to buy and sell, but Ebay
don't sell anything.
Kelkoo is a comparison website, where
it looks up in all the other website the best value for what you are looking
for.
Remember each of these is a virtual store like a superstore or shop.
You will go in the entrance (the homepage), go to the various departments
that you want to look in, chose your items and put them in a basket, then
go to the check-out and pay for your items.