I am not an accountant and do not fully(meaning no clue) about how the tax will reduce the cost of a share.

Let us say I buy it at 50 cents, thats my cost; If I sell at some different prices there will be a tax issue; If I gain, roughly 25% of the gain goes to Revenue Canada and if Loose I only loose 75% of that paper loss, since the loss can be carried towards a gain.

As far as I know if I buy a share at a given price, that is what I pay and there are no tax implications at that point in time?

Please clarify what I am missing