I know the difference will be prices, but still adding thousands of products will not be a good idea for your hosting. Now a days in such saturated environment, its possible to start and stick with small and narrow niche where you can make your site / store ass authority. But it can not be done if you make a super store. Because in that case your competetion will be with giants like Amazon, ebay and others.. Which obviously you can not compete because they have budget of billions of $. So, what that will be ? A complete disaster.